i experienced the same error when trying to use ipython notebook. i was a bit puzzled, when i noted, that another user on the same machine didn't rise this error. digging into it, i found, that it only occured, when the file .matplotlib/fontList.cache was missing in my home directory.
Here's my my file: https://srsoftware.de/sites/srsoftware.de/files/fontList.cache -- You received this message because you are subscribed to the Google Groups "sage-support" group. To unsubscribe from this group and stop receiving emails from it, send an email to sage-support+unsubscr...@googlegroups.com. To post to this group, send email to sage-support@googlegroups.com. Visit this group at http://groups.google.com/group/sage-support. For more options, visit https://groups.google.com/d/optout.
