Ellen

Are the macro's/the form in an addin?

If not this is probably the way to go - don't use the Macro assign
wizard but but just call a method (the macro) from the button click
event from the form code (as you would in VB6).

If the user has opened more than one file, which have macros of the
same name Excel can get confused.

If you put your macro code in an addin and reference the addin from the
files themselves this may get around your problem. Though I have to
say I've not come across the problem you have described.

Hope you sort it.
Mark