I finally stumbled across the answer in the help files.  I had inadvertantly set the file up to be shared and could not remove it from that status until I unprotected the workbook.  I saw that the file was shared but didn't think to look to see if that was the problem.  Once I searched the help files for share workbook I was able to zero in on the problem.

I hope this is helpful if anyone else runs into the problem.