Avast 4.8 and Outlook 2007

I just recently installed Outlook 2007 (actually the whole suite of Office 2007) and now, everytime I exit from Outlook I get a message box saying that:

Microsoft Office Outlook has encountered a problem and needs to close.

What do I need to do to stop this message?

Jim Elting

Any other antivirus or antispam in this computer? And in the past?
Why aren’t you with version 5 of avast?