Fix Courses_CourseModel::findLatestOfRequest() to not bomb out when given an empty array.

application/modules/courses/models/CourseModel.php

@@ -284,6 +284,9 @@ class Courses_CourseModel extends Unl_Model
         $db = Zend_Registry::get('db');
 
         if (Unl_Util::isArray($request)) {
+        	if (count($request) == 0) {
+        		return new Unl_Model_Collection(__CLASS__);
+        	}
             $requestId = array();
             foreach ($request as $aRequest) {
                 $requestId[] = $aRequest->getId();