Comment 1 for bug 487885

Since I do not see any of my own code in that traceback, I can only Google for that error to try to figure out why Distribute would be raising it. The results of my search suggest that the version of Distribute you are using, version 0.6.4, is flawed and that you need to upgrade to the most recent 0.6.8.

Could you try upgrading distribute with something like:

easy_install -U distribute

and then re-running the PyEphem install to see what happens?