If you notice the Exchange 2003 Connector for POP mail service if not running, I found the solution here: http://support.microsoft.com/kb/833992

I was getting the following error in the event log “CreateEvent(ServiceStop) Error: Cannot create a file when that file already exists.”

Basically I just killed the Imbdownl.exe process and it let me start the service and ran normally after that. There is also a hotfix to download at the link above, but I did not use it.