Fix to Email Course Info approval action when no previous request exists.

application/modules/courses/models/ApprovalActionEmailCourseInfoModel.php

@@ -142,7 +142,9 @@ class Courses_ApprovalActionEmailCourseInfoModel extends Requests_ApprovalAction
         $previousRequests = Requests_RequestModel::find($previousRequestIds);
         $this->_requestPreviousRequests = new Unl_Model_Collection('Requests_RequestModel');
         foreach ($previousRequestIds as $childId => $parentId) {
-        	$this->_requestPreviousRequests[$childId] = $previousRequests[$parentId];
+        	if ($previousRequests[$parentId]) {
+                $this->_requestPreviousRequests[$childId] = $previousRequests[$parentId];
+        	}
         }
         
         $ownerIds = array();