diff -Naur moodle/course/modlib.php moodle30/course/modlib.php
--- moodle/course/modlib.php	2016-04-07 11:30:44.000000000 +0530
+++ moodle30/course/modlib.php	2016-04-11 22:17:24.905873327 +0530
@@ -129,7 +129,7 @@
         context_helper::delete_instance(CONTEXT_MODULE, $moduleinfo->coursemodule);
         $DB->delete_records('course_modules', array('id'=>$moduleinfo->coursemodule));
 
-        if ($e instanceof moodle_exception) {
+        if ((isset($e) || is_null($e)) && ($e instanceof moodle_exception)) {
             throw $e;
         } else if (!is_number($returnfromfunc)) {
             print_error('invalidfunction', '', course_get_url($course, $moduleinfo->section));