Error on excel 2003 fm20.dll

I can't add command buttons on my excel sheets, nor click or operate via code ( error 438 on execution ).

I think it's a problem related with fm20.dll in system32 folder ( using windows xp sp2 ).

Any clue on how to solve this ??
Thanks!

I know this probably won't be helpful, but just so this thread has some reply...

The bottom section of this MSDN support page (http://support.microsoft.com/kb/200271) deals some causes of error 438.

There is a "hot fix" for Excel 2003 that is said to deal with error code 438 in some cases of worksheets with VBA controls:
http://support.microsoft.com/kb/890205

I have also had this issue when I upgraded from Excel 2003 to Excel 2007.
In Excel 2007 you can actually have two different types of command buttons - an ActiveX control type and a Forms control type...so some dlls are updated along with some registry entries as part of the upgrade.

Later, I ended up taking off Excel 2007 (backward compatibility reasons with users who couldn't learn to save spreadsheets as non-xml versions) and reinstalling Excel 2003 but for some reason every time I tried a new Excel 2003 VBA command button after that I always got error 438.
The solution was to use a restore point prior to the Office 2007 upgrade.

I also had one user who decided to use the Compatibility pack (http://www.microsoft.com/downloads/details.aspx?familyid=941b3470-3ae9-4aee-8f43-c6bb74cd1466&displaylang=en) and this caused him to throw 438 errors with my previously error free vba macros, but several others who installed this pack reported no issue. I ended up copying (updating) all the dlls in his Window directory with those for a machine that wasn't having issues and that solved the errors, but I didn't have time to see if it was a different fm20.dll version that was causing the issue (just brute forced the solution, sorry).