Actually, we figured it out.  The reports that are available are actually titled "uninvoiced charges" and "uninvoiced time", but when you run the report, the report is titled "unbilled charges".  That's just to keep everyone confused.  Anyway, running the uninvoiced charges report did come up with some items, but under someone's name other than this employee's name.  However, opening up those charges showed a check, and the check was indeed under this employee's name, with several items on it that had a check mark on "billable"!  Unchecking those checkmarks on the check and saving it allowed us to make the employee inactive.  Makes no sense, but it worked.  Hmm..