diff --git a/common/lib/capa/capa/responsetypes.py b/common/lib/capa/capa/responsetypes.py
index bd5a588c27..dc0fd518ee 100644
--- a/common/lib/capa/capa/responsetypes.py
+++ b/common/lib/capa/capa/responsetypes.py
@@ -8,7 +8,6 @@ Used by capa_problem.py
 '''
 
 # standard library imports
-import hashlib
 import inspect
 import json
 import logging
@@ -17,7 +16,6 @@ import numpy
 import random
 import re
 import requests
-import time
 import traceback
 import abc
 
@@ -856,18 +854,12 @@ class CodeResponse(LoncapaResponse):
             raise Exception(err)
 
         self.context.update({'submission': submission})
-        extra_payload = {'edX_student_response': submission}
 
         # Prepare xqueue request
         #------------------------------------------------------------ 
 
-        # Queuekey generation
-        h = hashlib.md5()
-        h.update(str(self.system.seed))
-        h.update(str(time.time()))
-        queuekey = h.hexdigest()
-
         # Generate header
+        queuekey = xqueue_interface.make_hashkey(self.system.seed)
         xheader = xqueue_interface.make_xheader(lms_callback_url=self.system.xqueue_callback_url,
                                                 lms_key=queuekey,
                                                 queue_name=self.queue_name)
@@ -886,7 +878,7 @@ class CodeResponse(LoncapaResponse):
 
         cmap = CorrectMap() 
         if error:
-            cmap.set(self.answer_id, msg='Unable to deliver your submission to grader! Please try again later')
+            cmap.set(self.answer_id, queuekey=None, msg='Unable to deliver your submission to grader! Please try again later')
         else:
             # Non-null CorrectMap['queuekey'] indicates that the problem has been queued 
             cmap.set(self.answer_id, queuekey=queuekey, msg='Submitted to grader')
diff --git a/lms/djangoapps/courseware/xqueue_interface.py b/lms/djangoapps/courseware/xqueue_interface.py
index 2bb7bed297..8ae8b6b441 100644
--- a/lms/djangoapps/courseware/xqueue_interface.py
+++ b/lms/djangoapps/courseware/xqueue_interface.py
@@ -1,8 +1,10 @@
 #
 #  LMS Interface to external queueing system (xqueue)
 #
+import hashlib
 import json
 import requests
+import time
 
 from boto.s3.connection import S3Connection
 from boto.s3.key import Key
@@ -39,6 +41,15 @@ def upload_files_to_s3(submission_file):
     print s3_identifier
     return s3_identifier
 
+def make_hashkey(seed=None):
+    '''
+    Generate a string key by hashing 
+    '''
+    h = hashlib.md5()
+    if seed is not None:
+        h.update(str(seed))
+    h.update(str(time.time()))
+    return h.hexdigest()
 
 def make_xheader(lms_callback_url, lms_key, queue_name):
     '''