I have a big problem!

I have a "meny sheet" with al ot of controlbuttons that links to other
workboks. When a user want to see a chart placed in another book, he
uses a userform to get there. The problem comes when he presses the
"Exit" button placed on this chart sheet!

The button runs the code
Activeworkbook.close true

and after he saved it and closed the book the whole excel generates an
error wich shut down excel!! This is not good if users work with other
book at the same time!

Anyone got a clue whats wrong??!

Daniel