If user does not exist, catch exception

User = None

symposion/proposals/views.py

@@ -137,6 +137,8 @@ def proposal_speaker_manage(request, pk):
             # check if email is on the site now
             try:
                 user = User.objects.get(email=email_address)
+            except ObjectDoesNotExist:
+                user = None
             except MultipleObjectsReturned:
                 # FIXME: This is not handled in the previous code, so I'm not
                 # going to frett on this now, but should be handled as it is