"Ambiguous Name Detected" Problem

I wrote a macro that creates a new worksheet, and among other things it adds an AutoShape rectangle that I use for a button. I assigned the macro named "DeleteListSheet" to the button. This encourages the user to delete the temporary sheet I created when he's finished with it. I ran this macro many times and used the "Delete" button to delete the sheets without mishap.
Then I copied the macros over to Personal.xls and began testing it. All went well until I tried to delete the sheet via that button. I got the message "Ambiguous Name Detected: DeleteListSheet." I verified that the macro assigned to the button was "Personal.xls!DeleteListSheet" so that there should have been no ambiguity with the original copy of that macro in my Test workbook.
Then I tried running the original version in my Test workbook, and got the same ambiguity message there too.
Next I clicked on the MACROS button to show the list of macros in Personal.xls, and the "DeleteListSheet" was not listed. I ran my own "ListAllMacros" for Personal.xls, and the macro name appeared on the list that my macro printed.
For the life of me, I can't figure out where the ambiguity is and why the "MACROS" list for Personal.xls doesn't show the macro name "DeleteListSheet". Also, why does my original (previously working) macro now have the same ambiguity. :banghead: