diff --git a/lti_tool_provider.module b/lti_tool_provider.module
index a3a8657..e847912 100644
--- a/lti_tool_provider.module
+++ b/lti_tool_provider.module
@@ -307,10 +307,10 @@ function lti_tool_provider_unassign_global_roles_from_user($lti_roles, $uid) {
  *   to meet the protocol.
  */
 function lti_tool_provider_is_basic_lti_request() {
-  $good_message_type = array_key_exists('lti_message_type', $_REQUEST) ? $_REQUEST["lti_message_type"] : "basic-lti-launch-request";
-  $good_lti_version = array_key_exists('lti_version', $_REQUEST) ? $_REQUEST["lti_version"] : "LTI-1p0";
+  $good_message_type = array_key_exists('lti_message_type', $_REQUEST) ? $_REQUEST["lti_message_type"] : NULL;
+  $good_lti_version = array_key_exists('lti_version', $_REQUEST) ? $_REQUEST["lti_version"] : NULL;
   $resource_link_id = array_key_exists('resource_link_id', $_REQUEST) ? $_REQUEST["resource_link_id"] : NULL;
-  if ($good_message_type and $good_lti_version and isset($resource_link_id)) {
+  if ($good_message_type == 'basic-lti-launch-request' && in_array($good_lti_version, array('LTI-1p0', 'LTI-1p2')) && isset($resource_link_id)) {
     return TRUE;
   }
   return FALSE;
@@ -332,6 +332,8 @@ function lti_tool_provider_get_lti_roles() {
     'Mentor',
     'Administrator',
     'TeachingAssistant',
+    'Else',
+    'Alumni'
   );
 }
 
@@ -751,4 +753,4 @@ function lti_tool_provider_consumer_access($op, $item = NULL, $account = NULL) {
   }
   // they didn't have viewer rights ignore this call
   return FALSE;
-}
\ No newline at end of file
+}
diff --git a/lti_tool_provider.operations.inc b/lti_tool_provider.operations.inc
index 1bf06e6..a99eb22 100644
--- a/lti_tool_provider.operations.inc
+++ b/lti_tool_provider.operations.inc
@@ -26,14 +26,24 @@ function lti_tool_provider_launch() {
   global $user;
   // If not an LTI launch request, then ignore.
   if (!lti_tool_provider_is_basic_lti_request()) {
-    drupal_set_message(t('Not a LTI request.'), 'info');
-    return t('Error: Not a LTI request.');
+    if (isset($_REQUEST['launch_presentation_return_url'])) {
+      lti_tool_provider_goto(url($_REQUEST['launch_presentation_return_url'], array('query' => array('lti_errormsg' => t('Error: Not a LTI request.')))));
+    }
+    else {
+      drupal_set_message(t('Error: Not a LTI request.'), 'error');
+      return t('Error: Not a LTI request.');
+    }
   }
   // Insure we have a valid context.
   if (empty($_REQUEST['oauth_consumer_key'])) {
     unset($_SESSION['lti_tool_provider_context_info']);
-    drupal_set_message(t('Not a valid LTI context.'), 'info');
-    return t('Error: Invalid context. Missing oauth_consumer_key in request.');
+    if (isset($_REQUEST['launch_presentation_return_url'])) {
+      lti_tool_provider_goto(url($_REQUEST['launch_presentation_return_url'], array('query' => array('lti_errormsg' => t(t('Not a valid LTI context.'))))));
+    }
+    else {
+      drupal_set_message(t('Error: Invalid context. Missing oauth_consumer_key in request.'), 'error');
+      return t('Error: Invalid context. Missing oauth_consumer_key in request.');
+    }
   }
   // Begin a new session based on this LTI launch request.
   drupal_session_start();
@@ -48,19 +58,24 @@ function lti_tool_provider_launch() {
     $server->verify_request($request);
     // This is a LTI launch request.
   } catch (Exception $e) {
-    drupal_set_message(check_plain($e->getMessage()), 'error');
-    return t('Error: Invalid context, OAuth failure.');
+    if (isset($_REQUEST['launch_presentation_return_url'])) {
+      lti_tool_provider_goto(url($_REQUEST['launch_presentation_return_url'], array('query' => array('lti_errormsg' => t('Error: Invalid context, OAuth failure.')))));
+    }
+    else {
+      drupal_set_message(check_plain($e->getMessage()), 'error');
+      return t('Error: Invalid context, OAuth failure.');
+    }
   }
   // Collect the launch information for later storage in the session.
   $launch_info = $request->get_parameters();
-  if (empty($launch_info['context_id'])) {
+  /*if (empty($launch_info['context_id'])) {
     if (isset($launch_info['launch_presentation_return_url'])) {
       lti_tool_provider_goto(url($launch_info['launch_presentation_return_url'], array('query' => array('lti_errormsg' => t('Error: Invalid context, No context Id.')))));
     }
     else {
       return t('Error: Invalid context, No context Id.');
     }
-  }
+  }*/
   $consumer = lti_tool_provider_get_consumer_by_key($oauth_consumer_key);
   $launch_info['consumer_id'] = $consumer->lti_tool_provider_consumer_id;
   $launch_info['consumer_domain'] = $consumer->lti_tool_provider_consumer_domain;
diff --git a/lti_tool_provider_memberships/lti_tool_provider_memberships.module b/lti_tool_provider_memberships/lti_tool_provider_memberships.module
index 8f7b8d4..7c5e6c5 100644
--- a/lti_tool_provider_memberships/lti_tool_provider_memberships.module
+++ b/lti_tool_provider_memberships/lti_tool_provider_memberships.module
@@ -25,7 +25,7 @@ function lti_tool_provider_memberships_menu() {
     'description' => 'Configure LTI Memberships groups.',
     'page callback' => 'drupal_get_form',
     'page arguments' => array('lti_tool_provider_memberships_subgroup_mapping'),
-    'access callback' => 'lti_tool_provider_memberships_access_and_og', 
+    'access callback' => 'lti_tool_provider_memberships_access_and_og',
     'access arguments' => array('administer lti_tool_provider module'),
     'file' => 'lti_tool_provider_memberships.admin.inc',
     'weight' => -3,
@@ -911,18 +911,25 @@ function lti_tool_provider_memberships_lti_tool_provider_launch_alter(&$launch_i
   // If user does not have a membership, create one
   global $user;
   $query = new EntityFieldQuery();
-  $result = $query
-  -> entityCondition('entity_type', 'lti_tool_provider_memberships')
-  -> propertyCondition('lti_tool_provider_memberships_context_id', $launch_info['context_id'])
-  -> propertyCondition('lti_tool_provider_memberships_user_id', $launch_info['user_id'])
-  -> execute();
+  $result = $query->entityCondition('entity_type', 'lti_tool_provider_memberships');
+  // can't assume context_id isset, not required by IMS specification
+  if (isset($launch_info['context_id'])) {
+    $result->propertyCondition('lti_tool_provider_memberships_context_id', $launch_info['context_id']);
+  }
+  // can't assume user_id is set when working with guest access
+  if (isset($launch_info['user_id'])) {
+    $result->propertyCondition('lti_tool_provider_memberships_user_id', $launch_info['user_id']);
+  }
+  $result->execute();
   if (empty($result)) {
     $entity = entity_get_controller('lti_tool_provider_memberships')->create();
     $entity->lti_tool_provider_memberships_context_id = $launch_info['context_id'];
     $entity->lti_tool_provider_memberships_uid = isset($account->uid) ? $account->uid : NULL;
     $entity->lti_tool_provider_memberships_user_id = $launch_info['user_id'];
     $entity->lti_tool_provider_memberships_role = $launch_info['roles'];
-    $entity->lti_tool_provider_memberships_person_name_full = $launch_info['lis_person_name_full'];
+    if (isset($launch_info['lis_person_name_full'])) {
+      $entity->lti_tool_provider_memberships_person_name_full = $launch_info['lis_person_name_full'];
+    }
     lti_tool_provider_memberships_save($entity);
   }
 }
diff --git a/lti_tool_provider_og/lti_tool_provider_og.module b/lti_tool_provider_og/lti_tool_provider_og.module
index 2e437d3..6d33d5e 100644
--- a/lti_tool_provider_og/lti_tool_provider_og.module
+++ b/lti_tool_provider_og/lti_tool_provider_og.module
@@ -127,7 +127,7 @@ function lti_tool_provider_og_lti_tool_provider_launch_alter(&$launch_info, $acc
     foreach (og_get_all_group($group_entity) as $key => $group_id) {
       $group_wrapper = entity_metadata_wrapper($group_entity, $group_id);
       $fields = $group_wrapper->getPropertyInfo();
-      if (isset($fields[$mapping_field]) && $group_wrapper->{$mapping_field}->value() == $launch_info['context_id']) {
+      if (isset($fields[$mapping_field]) && isset($launch_info['context_id']) && $group_wrapper->{$mapping_field}->value() == $launch_info['context_id']) {
         // Found the group that matches the context_id.
         $course_found = TRUE;
         $launch_info['course_entity_type'] = $group_entity;
@@ -152,7 +152,7 @@ function lti_tool_provider_og_lti_tool_provider_launch_alter(&$launch_info, $acc
     }
     // Provision group.
     // FIX THIS does not cope with non-node group bundles.
-    if (!$course_found && ($launch_info['context_id'] != NULL) &&
+    if (!$course_found && isset($launch_info['context_id']) && ($launch_info['context_id'] != NULL) &&
       (variable_get('lti_tool_provider_og_provision_groups') == 1) &&
       ((variable_get('lti_tool_provider_og_provision_groups_anon') == 1) || (user_access('create ' . $group_bundle . ' content', $account)))) {
       $node = new stdClass();
@@ -189,7 +189,13 @@ function lti_tool_provider_og_lti_tool_provider_launch_alter(&$launch_info, $acc
       $launch_info['destination'] = $launch_info['course_entity_type'] . '/' . $launch_info['course_entity_eid'];
     }
     else {
-      drupal_set_message(t('No course corresponding to @label exists.', array('@label' => $launch_info['context_label'])));
+      if (isset($launch_info['context_label'])) {
+        $label = $launch_info['context_label'];
+      }
+      else {
+        $label = '<none>';
+      }
+      drupal_set_message(t('No course corresponding to @label exists.', array('@label' => $label)));
     }
   }
 }
diff --git a/lti_tool_provider_outcomes/lti_tool_provider_outcomes.module b/lti_tool_provider_outcomes/lti_tool_provider_outcomes.module
index 5c79122..e97f0da 100644
--- a/lti_tool_provider_outcomes/lti_tool_provider_outcomes.module
+++ b/lti_tool_provider_outcomes/lti_tool_provider_outcomes.module
@@ -749,6 +749,9 @@ function lti_tool_provider_outcomes_lti_tool_provider_create_account_alter(&$acc
       // Set the resultvalue_sourcedids in the lti info.
       $lti_info['resultvalue_sourcedids'] = isset($lti_info['ext_ims_lis_resultvalue_sourcedids']) ? $lti_info['ext_ims_lis_resultvalue_sourcedids'] : 'decimal';
       // Create the resource.
+      if (!isset($lti_info['resource_link_title'])) {
+        $lti_info['resource_link_title'] = '';
+      }
       $lti_info['resource_id'] = lti_tool_provider_outcomes_get_set_resource($lti_info['consumer_id'], $lti_info['context_id'], $lti_info['resource_link_id'], $lti_info['resource_link_title'], $lti_info['resultvalue_sourcedids']);
     }
     // Create or update the outcome.
@@ -763,4 +766,4 @@ function lti_tool_provider_outcomes_lti_tool_provider_memberships_get_alter(&$me
   if (isset($member_data->lis_result_sourcedid)) {
     $member['lis_result_sourcedid'] = (string)$member_data->lis_result_sourcedid;
   }
-}
\ No newline at end of file
+}