This course in studio has many images which presumably is keeping export from working:
The course team needs to use import/export to add polls.
To reproduce, go to https://studio.edx.org/export/slashes:VJx+VJx+3T2014 and click export. It will time out or give an error:
There has been an error with your export.
There has been a failure to export your course to XML. Unfortunately, we do not have specific enough information to assist you in identifying the failed component. It is recommended that you inspect your courseware to identify any components in error and try again.
The raw error message is:
[Errno 28] No space left on device