Outlook Closes After Marking "This Is Spam"

I've been running Win7 with Norton Internet Security version 17.8.0.5 and I've not changed anything.  I'm  using Microsoft Office Outlook 2007 and have had it on my laptop since I got it new about six months ago. 

 

All of a sudden when I click on an email to mark it as spam it says Outlook has encountered a problem and needs to close. 

 

Can anyone please tell me what I should look for to correct this issue?

 

Regards,

 

Lynn McClure