Do you happen to have two workbooks open?
What about the workbook that IS open?
Does it have macros in it?
try opening a NEW workbook (only one) and see if it works.
I'm not sure what error 53 is, (can't look it up right now)
but I'm guessing there is a conflict with the form located
in the Personal.xls file. for that matter, ANY form located
in one workbook (like Personal.xls) being "called" from another
workbook is "messy"..
In order for the name to be found, the settings in excel must
ALLOW the application to look in workbooks other than the current one.

By default, unless told otherwise, Excel "assumes" Activeworkbook....
so.. it may be the the user's settings (security?) may be
disabling the ability to automatically search workbooks not "current".

Have you "loaded" the userform?

I tried this in Excel2007 and could not load or show the userform.
I'll have to investigate further to figure out how to load a form not in the
current workbook.