Excel helper

I built a small application that uses a UserForm wizard to complete a task.
The userform is launched from a menu item that I placed on the worksheet menu
bar.

I gave it to 3 friends and it worked fine for 2 of them but not for the
other. For the 2 friends that had no problems they use Excel 2003. The other
individual uses Excel 2002 and when he clicked the menu itme to start the
wizard an error was generated :

Compile Error

Can't find project or library

Is there any reason why this would be the case? The wizard is quite simple
and I can't see that it uses anything that is only available in 2003.

Regards


Alex