Extended GMap not showing marker(s) for user locations

Hello all,

I'm having a problem with the Extended GMap. It simply will never show any markers for user locations. The standard Gmap format is working correctly but no success with Extended. My view is as follows:

$view = new view();
$view->name = 'usermap';
$view->description = '';
$view->tag = 'default';
$view->base_table = 'users';
$view->human_name = 'UserMap';
$view->core = 7;
$view->api_version = '3.0';
$view->disabled = FALSE; /* Edit this to true to make a default view disabled initially */

/* Display: Master */
$handler = $view->new_display('default', 'Master', 'default');
$handler->display->display_options['title'] = 'Map';
$handler->display->display_options['use_more_always'] = FALSE;
$handler->display->display_options['access']['type'] = 'perm';
$handler->display->display_options['access']['perm'] = 'access user profiles';
$handler->display->display_options['cache']['type'] = 'none';
$handler->display->display_options['query']['type'] = 'views_query';
$handler->display->display_options['exposed_form']['type'] = 'basic';
$handler->display->display_options['pager']['type'] = 'some';
$handler->display->display_options['pager']['options']['items_per_page'] = '1';
$handler->display->display_options['style_plugin'] = 'gmapextended';
$handler->display->display_options['style_options']['fallback_values'] = array(
  'text' => '',
  'rmt' => '',
  'iwq' => '',
  'iwo' => '',
  'link' => '',
  'latitude' => '',
  'longitude' => '',
  'title' => '',
  'markername' => '',
  'offset' => '',
);
$handler->display->display_options['style_options']['field_purposes'] = array(
  'name' => '',
  'uid' => '',
  'latitude' => 'latitude',
  'longitude' => 'longitude',
);
$handler->display->display_options['style_options']['datasource'] = 'fields';
$handler->display->display_options['style_options']['center_on_proximityfilter_rel'] = 'none';
$handler->display->display_options['row_plugin'] = 'fields';
/* Field: User: Name */
$handler->display->display_options['fields']['name']['id'] = 'name';
$handler->display->display_options['fields']['name']['table'] = 'users';
$handler->display->display_options['fields']['name']['field'] = 'name';
$handler->display->display_options['fields']['name']['label'] = '';
$handler->display->display_options['fields']['name']['alter']['word_boundary'] = FALSE;
$handler->display->display_options['fields']['name']['alter']['ellipsis'] = FALSE;
/* Field: User: Uid */
$handler->display->display_options['fields']['uid']['id'] = 'uid';
$handler->display->display_options['fields']['uid']['table'] = 'users';
$handler->display->display_options['fields']['uid']['field'] = 'uid';
/* Field: Location: Latitude */
$handler->display->display_options['fields']['latitude']['id'] = 'latitude';
$handler->display->display_options['fields']['latitude']['table'] = 'location';
$handler->display->display_options['fields']['latitude']['field'] = 'latitude';
$handler->display->display_options['fields']['latitude']['label'] = '';
$handler->display->display_options['fields']['latitude']['element_label_colon'] = FALSE;
/* Field: Location: Longitude */
$handler->display->display_options['fields']['longitude']['id'] = 'longitude';
$handler->display->display_options['fields']['longitude']['table'] = 'location';
$handler->display->display_options['fields']['longitude']['field'] = 'longitude';
$handler->display->display_options['fields']['longitude']['label'] = '';
$handler->display->display_options['fields']['longitude']['element_label_colon'] = FALSE;
/* Sort criterion: User: Created date */
$handler->display->display_options['sorts']['created']['id'] = 'created';
$handler->display->display_options['sorts']['created']['table'] = 'users';
$handler->display->display_options['sorts']['created']['field'] = 'created';
$handler->display->display_options['sorts']['created']['order'] = 'DESC';
/* Contextual filter: User: Uid */
$handler->display->display_options['arguments']['uid']['id'] = 'uid';
$handler->display->display_options['arguments']['uid']['table'] = 'users';
$handler->display->display_options['arguments']['uid']['field'] = 'uid';
$handler->display->display_options['arguments']['uid']['default_action'] = 'default';
$handler->display->display_options['arguments']['uid']['default_argument_type'] = 'user';
$handler->display->display_options['arguments']['uid']['default_argument_options']['user'] = TRUE;
$handler->display->display_options['arguments']['uid']['summary']['number_of_records'] = '0';
$handler->display->display_options['arguments']['uid']['summary']['format'] = 'default_summary';
$handler->display->display_options['arguments']['uid']['summary_options']['items_per_page'] = '25';
$handler->display->display_options['arguments']['uid']['validate']['type'] = 'user';
$handler->display->display_options['arguments']['uid']['validate_options']['type'] = 'either';
/* Filter criterion: User: Active */
$handler->display->display_options['filters']['status']['id'] = 'status';
$handler->display->display_options['filters']['status']['table'] = 'users';
$handler->display->display_options['filters']['status']['field'] = 'status';
$handler->display->display_options['filters']['status']['value'] = '1';
$handler->display->display_options['filters']['status']['group'] = 1;
$handler->display->display_options['filters']['status']['expose']['operator'] = FALSE;
/* Filter criterion: Location: Distance / Proximity */
$handler->display->display_options['filters']['distance']['id'] = 'distance';
$handler->display->display_options['filters']['distance']['table'] = 'location';
$handler->display->display_options['filters']['distance']['field'] = 'distance';
$handler->display->display_options['filters']['distance']['value'] = array(
  'latitude' => '',
  'longitude' => '',
  'postal_code' => '',
  'country' => '',
  'php_code' => '',
  'nid_arg' => '',
  'nid_loc_field' => 'node',
  'uid_arg' => 'uid',
  'search_distance' => '100',
  'search_units' => 'mile',
);

/* Display: User Map Block */
$handler = $view->new_display('block', 'User Map Block', 'block');

/* Display: Block */
$handler = $view->new_display('block', 'Block', 'block_1');
$handler->display->display_options['defaults']['style_plugin'] = FALSE;
$handler->display->display_options['style_plugin'] = 'default';
$handler->display->display_options['defaults']['style_options'] = FALSE;
$handler->display->display_options['defaults']['row_plugin'] = FALSE;
$handler->display->display_options['row_plugin'] = 'fields';
$handler->display->display_options['defaults']['row_options'] = FALSE;

Any advice would be much appreciated!