Outlook '07 -"unsent message error"

Hi, sorry to do this, but I gotta throw a computer question out to the GQ forum.
For the record I hate Outlook and don’t use it, but my client does and he is receiving messages when he closes Outlook that there are still unsent messages in the outbox and are you sure you want to exit anyway?

Upon inspecting the outbox, you find… n-othing. I ran a repair on MS Office this afternoon and apparently his Outlook is running slower now and he still has this message coming up. Any ideas on the message guys?

I ha-ve googled and I’ll keep looking, but if someone has come across this issue before or might know some way to solve this, I’d appreciate any suggestions. Thanks in advance.

Wow… nobody huh?.. that’s a surprise.