I've never seen this error, which appears to be coming from the Jobe server. A web search for your error brings up a bug report that on Debian stretch:
unshare -r, when executed as normal user (uid=1000) fails with 'operation not permitted'
However, why the unshare program is being called at all I have no idea. It's not used anywhere in the source code for Moodle, CodeRunner or Jobe.
You appear to be running a Lisp program which isn't part of the standard CodeRunner or Jobe installs, so my guess is that the message relates to your install of Lisp. Alternatively I see some web discussion around the use of unshare in lxc containers. Are you using a standard Jobe install or have you tried to containerise it yourself? Can you confirm please that the CodeRunner built-in question types work OK?
Tell me more about your Jobe server. You say "Code Runner server: Debian 7.6", is that the Jobe server? Does you Jobe server run the standard test program, testsubmit.py, ok? What tests have you done to ensure that the lisp you've (presumably) installed on Jobe works ok?