Problem with the group activity block...

I reopen a old problem without solution (http://drupal.org/node/1717846) with new information to help to debug the situation.

I received this notice: Notice: to get property of non-object in detectGroup() line 36

I printed some variables in the beggining of the detectGroup function to help to understand the problem and I put the trace from Devel in attachment. Can you help to resolve this problem with these informations?
If you want, I can try other dvm() somewhere else. I dont have the knowledge to debug better than that! I'm sorry.

Thanks in advance for your help.

Variable $og_context : NULL

Variable og_context():

array(
'group_type' => 'node',
'gid' => '1002',
)

Variable $this:
GroupActivity::__set_state(array(
'nid' => 0,
'og_context' => NULL,
'group' => NULL,
'query' => NULL,
'config' =>
HeartbeatStreamConfig::__set_state(array(
'name' => 'Group activity',
'class' => 'groupactivity',
'real_class' => 'groupactivity',
'path' => 'streams/groupactivity.inc',
'title' => 'Activité du groupe',
'module' => 'heartbeat_plugins',
'variables' =>
array (
),
'has_block' => 1,
'block_items_max' => '5',
'block_show_pager' => '1',
'block_view_mode' => 'default',
'page_items_max' => '20',
'page_show_pager' => 0,
'page_pager_ajax' => 0,
'page_view_mode' => 'default',
'show_message_times' => 1,
'show_message_times_grouped' => 1,
'messages_denied' =>
array (
'heartbeat_add_comment' => 0,
'heartbeat_add_grouppost' => 0,
'heartbeat_add_node' => 0,
'heartbeat_become_group_member' => 0,
'heartbeat_edit_account' => 0,
'heartbeat_edit_node' => 0,
'heartbeat_tweet' => 0,
),
'num_load_max' => '100',
'grouping_seconds' => '7200',
'skip_active_user' => 0,
'poll_messages' => '0',
'poll_messages_type' => '0',
'stream_path' => 'activites/groupe',
'stream_profile_path' => '',
'settings' =>
array (
'settings__active_tab' => 'edit-settings-fs-pages',
'messages_denied' =>
array (
'heartbeat_add_comment' => 0,
'heartbeat_add_grouppost' => 0,
'heartbeat_add_node' => 0,
'heartbeat_become_group_member' => 0,
'heartbeat_edit_account' => 0,
'heartbeat_edit_node' => 0,
'heartbeat_tweet' => 0,
),
'skip_active_user' => 0,
'show_message_times' => 1,
'show_message_times_grouped' => 1,
'poll_messages' => '0',
'poll_messages_type' => '0',
'num_load_max' => '100',
'grouping_seconds' => '7200',
'has_block' => 1,
'block_items_max' => '5',
'block_show_pager' => '1',
'block_view_mode' => 'default',
'stream_path' => 'activites/groupe',
'stream_profile_path' => '',
'page_items_max' => '20',
'page_show_pager' => 0,
'page_pager_ajax' => 0,
'page_view_mode' => 'default',
'exclude_og' => 0,
),
'api_version' => 1,
'disabled' => false,
'export_module' => 'heartbeat_og',
'export_type' => 3,
'in_code_only' => false,
'table' => 'heartbeat_streams',
'type' => 'Supplanté',
'settings__active_tab' => 'edit-settings-fs-pages',
'exclude_og' => 0,
)),
'messages' =>
array (
),
'prefix' => '',
'suffix' => '',
'templates' =>
array (
2 =>
array (
'heartbeat_add_comment' =>
HeartbeatMessageTemplate::__set_state(array(
'hid' => '1',
'message_id' => 'heartbeat_add_comment',
'perms' => '2',
'description' => 'L\'utilisateur a répondu à certain contenu',
'message' => '!username a répondu à !title:
!comment
',
'message_concat' => '%username% a répondu à !title.',
'group_type' => 'summary',
'concat_args' =>
array (
'group_by' => 'node',
'group_target' => 'username',
'group_by_target' => 'title',
'group_num_max' => '5',
'merge_separator' => ', ',
'merge_end_separator' => ' et ',
'roles' =>
array (
3 => '3',
11 => '11',
12 => '12',
10 => '10',
7 => '7',
5 => '5',
6 => '6',
9 => '9',
1 => 0,
2 => 0,
4 => 0,
8 => 0,
),
),
'variables' =>
array (
'!username' => '',
'!title' => '',
'!comment' => '',
),
'attachments' =>
array (
),
'roles' =>
array (
),
'new_type' => NULL,
'base' => NULL,
'bundle' => '',
'api_version' => 1,
'disabled' => false,
'export_module' => 'heartbeat_defaults',
'export_type' => 3,
'in_code_only' => false,
'table' => 'heartbeat_messages',
'type' => 'Supplanté',
)),
'heartbeat_tweet' =>
HeartbeatMessageTemplate::__set_state(array(
'hid' => 0,
'message_id' => 'heartbeat_tweet',
'perms' => 2,
'description' => 'A custom message or tweet',
'message' => '!username !message',
'message_concat' => '',
'group_type' => 'single',
'concat_args' =>
array (
'group_by' => 'none',
'group_target' => '',
'group_by_target' => '',
'group_num_max' => '',
'merge_separator' => '',
'merge_end_separator' => '',
'roles' =>
array (
1 => 0,
2 => 0,
3 => 0,
4 => 0,
5 => 0,
),
),
'variables' =>
array (
'!username' => '',
'!message' => '',
),
'attachments' =>
array (
'buttons' =>
array (
'weight' =>
array (
'activitycomments' => -9,
),
'settings' =>
array (
'activitycomments' =>
array (
'activitycomments_node' => 0,
),
),
'enabled' =>
array (
'activitycomments' => 'activitycomments',
),
),
'content' =>
array (
'weight' =>
array (
'activitycomments' => -9,
),
'enabled' =>
array (
'activitycomments' => 'activitycomments',
),
),
),
'roles' =>
array (
),
'new_type' => NULL,
'base' => NULL,
'bundle' => '',
'api_version' => 1,
'disabled' => false,
'export_module' => 'heartbeat_defaults',
'export_type' => 2,
'in_code_only' => true,
'table' => 'heartbeat_messages',
'type' => 'Par défaut',
)),
),
4 =>
array (
'heartbeat_add_grouppost' =>
HeartbeatMessageTemplate::__set_state(array(
'hid' => '2',
'message_id' => 'heartbeat_add_grouppost',
'perms' => '4',
'description' => 'L\'utilisateur a posté dans le groupe, sauvegarder l\'activité de l\'utilisateur',
'message' => '!username a ajouté un !node_type !node_title dans le groupe !group.',
'message_concat' => 'username a ajouté %node_title% dans le groupe !group.',
'group_type' => 'summary',
'concat_args' =>
array (
'group_by' => 'node-target',
'group_target' => 'node_title',
'group_by_target' => 'group',
'group_num_max' => '3',
'merge_separator' => ', ',
'merge_end_separator' => ' et ',
'roles' =>
array (
11 => '11',
12 => '12',
10 => '10',
7 => '7',
5 => '5',
6 => '6',
9 => '9',
1 => 0,
2 => 0,
3 => 0,
4 => 0,
8 => 0,
),
),
'variables' =>
array (
'!username' => '',
'!node_type' => '',
'!node_title' => '',
'!group' => '',
),
'attachments' =>
array (
),
'roles' =>
array (
),
'new_type' => NULL,
'base' => NULL,
'bundle' => '',
'api_version' => 1,
'disabled' => false,
'export_module' => 'heartbeat_og',
'export_type' => 3,
'in_code_only' => false,
'table' => 'heartbeat_messages',
'type' => 'Supplanté',
)),
'heartbeat_add_node' =>
HeartbeatMessageTemplate::__set_state(array(
'hid' => '3',
'message_id' => 'heartbeat_add_node',
'perms' => '4',
'description' => 'L\'utilisateur a ajouté un contenu, sauvegarder l\'activité de l\'utilisateur',
'message' => '!username a ajouté un !node_type !node_title.',
'message_concat' => '!username a ajouté un contenu de type !types: %node_title%.',
'group_type' => 'summary',
'concat_args' =>
array (
'group_by' => 'user',
'group_target' => 'node_title',
'group_by_target' => 'username',
'group_num_max' => '4',
'merge_separator' => ', ',
'merge_end_separator' => ' et ',
'roles' =>
array (
3 => '3',
11 => '11',
12 => '12',
10 => '10',
7 => '7',
5 => '5',
6 => '6',
9 => '9',
1 => 0,
2 => 0,
4 => 0,
8 => 0,
),
),
'variables' =>
array (
'!username' => '',
'!node_type' => '',
'!node_title' => '',
'!types' => '',
),
'attachments' =>
array (
),
'roles' =>
array (
),
'new_type' => NULL,
'base' => NULL,
'bundle' => '',
'api_version' => 1,
'disabled' => false,
'export_module' => 'heartbeat_defaults',
'export_type' => 3,
'in_code_only' => false,
'table' => 'heartbeat_messages',
'type' => 'Supplanté',
)),
'heartbeat_become_group_member' =>
HeartbeatMessageTemplate::__set_state(array(
'hid' => '4',
'message_id' => 'heartbeat_become_group_member',
'perms' => '4',
'description' => 'Activité d\'un utilisateur devenant membre d\'un groupe',
'message' => '!username est devenu membre du groupe !group.',
'message_concat' => '%username% vient de devenir membre du groupe !group.',
'group_type' => 'summary',
'concat_args' =>
array (
'group_by' => 'node',
'group_target' => 'username',
'group_by_target' => 'group',
'group_num_max' => '5',
'merge_separator' => ', ',
'merge_end_separator' => ' et ',
'roles' =>
array (
3 => '3',
11 => '11',
12 => '12',
10 => '10',
7 => '7',
5 => '5',
6 => '6',
9 => '9',
1 => 0,
2 => 0,
4 => 0,
8 => 0,
),
),
'variables' =>
array (
'!username' => '',
'!group' => '',
),
'attachments' =>
array (
),
'roles' =>
array (
),
'new_type' => NULL,
'base' => NULL,
'bundle' => '',
'api_version' => 1,
'disabled' => false,
'export_module' => 'heartbeat_og',
'export_type' => 3,
'in_code_only' => false,
'table' => 'heartbeat_messages',
'type' => 'Supplanté',
)),
'heartbeat_edit_account' =>
HeartbeatMessageTemplate::__set_state(array(
'hid' => '5',
'message_id' => 'heartbeat_edit_account',
'perms' => '4',
'description' => 'L\'utilisateur a changé son compte',
'message' => 'La page personnel de l\'utilisateur !username a été changée.',
'message_concat' => 'La page personnelle de l\'utilisateur %username% a été changée.',
'group_type' => 'summary',
'concat_args' =>
array (
'group_by' => 'node',
'group_target' => 'username',
'group_by_target' => '',
'group_num_max' => '4',
'merge_separator' => ', ',
'merge_end_separator' => ' et ',
'roles' =>
array (
3 => '3',
12 => '12',
10 => '10',
7 => '7',
1 => 0,
2 => 0,
4 => 0,
8 => 0,
11 => 0,
5 => 0,
6 => 0,
9 => 0,
),
),
'variables' =>
array (
'!username' => '',
),
'attachments' =>
array (
),
'roles' =>
array (
),
'new_type' => NULL,
'base' => NULL,
'bundle' => '',
'api_version' => 1,
'disabled' => false,
'export_module' => 'heartbeat_defaults',
'export_type' => 3,
'in_code_only' => false,
'table' => 'heartbeat_messages',
'type' => 'Supplanté',
)),
'heartbeat_edit_node' =>
HeartbeatMessageTemplate::__set_state(array(
'hid' => '6',
'message_id' => 'heartbeat_edit_node',
'perms' => '4',
'description' => 'Activité d\'édition des utilisateurs',
'message' => '!username a modifié le contenu de type !node_type "!node_title".',
'message_concat' => '!username a mise à jour le contenu %node_title%.',
'group_type' => 'summary',
'concat_args' =>
array (
'group_by' => 'user',
'group_target' => 'node_title',
'group_by_target' => '',
'group_num_max' => '4',
'merge_separator' => ', ',
'merge_end_separator' => ' et ',
'roles' =>
array (
3 => '3',
12 => '12',
10 => '10',
7 => '7',
1 => 0,
2 => 0,
4 => 0,
8 => 0,
11 => 0,
5 => 0,
6 => 0,
9 => 0,
),
),
'variables' =>
array (
'!username' => '',
'!node_type' => '',
'!node_title' => '',
),
'attachments' =>
array (
),
'roles' =>
array (
),
'new_type' => NULL,
'base' => NULL,
'bundle' => '',
'api_version' => 1,
'disabled' => false,
'export_module' => 'heartbeat_defaults',
'export_type' => 3,
'in_code_only' => false,
'table' => 'heartbeat_messages',
'type' => 'Supplanté',
)),
),
),
'contextual_arguments' =>
array (
),
'templates_denied' =>
array (
),
'language' => 'und',
'exclude_og' => false,
'_uid' => '1',
'_errors' =>
array (
),
'_has_errors' => false,
'needsModal' => true,
'_offset_time' => 1365636189,
'oldest_date' => '7948800',
'messages_max' => '5',
'latest_activity_id' => 0,
'_page' => false,
'ajax' => false,
'canPage' => false,
'_whoisuser_type' => 0,
'viewer' =>
stdClass::__set_state(array(
'uid' => '1',
'name' => 'xxx',
'pass' => '*xxx',
'mail' => 'xxx',
'theme' => '',
'signature' => '',
'signature_format' => 'filtered_html',
'created' => '1361536368',
'access' => '1365635647',
'login' => '1365634687',
'status' => '1',
'timezone' => NULL,
'language' => 'fr',
'picture' => '0',
'init' => 'xxx',
'data' =>
array (
'ckeditor_default' => 't',
'ckeditor_show_toggle' => 't',
'ckeditor_width' => '100%',
'ckeditor_lang' => 'en',
'ckeditor_auto_lang' => 't',
'contact' => 1,
),
'uuid' => 'ba231f4d-45b5-db74-a1aa-f8cce1df3233',
'sid' => 'WYKEwt1y6rrYyXK7R13jPdwSwv1DgFjz3NIU8OCyroc',
'ssid' => '',
'hostname' => 'xxx',
'timestamp' => '1365635647',
'cache' => '0',
'session' => 'X7DcQlhz70VEGP22zucTX7Rc6MnKcAh6oclr7dERaFcNCPH0hJkI4jiKZ7hZbZKT3C7LFOr6b6d3nVE9A2zVnWs5ANGRo67IExGCcymJWKJ--yEodadC0gAcUiScTacV6wyg8nobBQ07QaXHaNuliu1dS1DenwTTSCI1e94l8FD-k4iTOLH2l14W_NZi8Gi5i4kwaFDNDGaN2EyRnAGzk-MQoaX1aa21_Dhpa0DW9XUiA2GOIoT-qClVfFSLtxTI',
'roles' =>
array (
2 => 'authenticated user',
3 => 'administrateur',
),
'privatemsg_disabled' => false,
)),
'viewed' =>
stdClass::__set_state(array(
'uid' => '1',
'name' => 'xxx',
'pass' => 'xxx',
'mail' => 'xxx',
'theme' => '',
'signature' => '',
'signature_format' => 'filtered_html',
'created' => '1361536368',
'access' => '1365635647',
'login' => '1365634687',
'status' => '1',
'timezone' => NULL,
'language' => 'fr',
'picture' => '0',
'init' => 'xxx',
'data' =>
array (
'ckeditor_default' => 't',
'ckeditor_show_toggle' => 't',
'ckeditor_width' => '100%',
'ckeditor_lang' => 'en',
'ckeditor_auto_lang' => 't',
'contact' => 1,
),
'uuid' => 'ba231f4d-45b5-db74-a1aa-f8cce1df3233',
'sid' => 'WYKEwt1y6rrYyXK7R13jPdwSwv1DgFjz3NIU8OCyroc',
'ssid' => '',
'hostname' => xxx',
'timestamp' => '1365635647',
'cache' => '0',
'session' => 'X7DcQlhz70VEGP22zucTX7Rc6MnKcAh6oclr7dERaFcNCPH0hJkI4jiKZ7hZbZKT3C7LFOr6b6d3nVE9A2zVnWs5ANGRo67IExGCcymJWKJ--yEodadC0gAcUiScTacV6wyg8nobBQ07QaXHaNuliu1dS1DenwTTSCI1e94l8FD-k4iTOLH2l14W_NZi8Gi5i4kwaFDNDGaN2EyRnAGzk-MQoaX1aa21_Dhpa0DW9XUiA2GOIoT-qClVfFSLtxTI',
'roles' =>
array (
2 => 'authenticated user',
3 => 'administrateur',
),
'privatemsg_disabled' => false,
)),
'view_mode' => 'default',
'_whoisuser_types' =>
array (
0 => 'Viewing user',
1 => 'Viewed user',
),
))