"Could not change to that identity"

Version: 2008
Operating System: Mac OS X 10.5 (Leopard)
Processor: Intel
Email Client: Exchange

An unknown error (-5000) occurred.

I was having a minor problem with Entourage not remembering my password and after IT was done with my system, Entourage is just completely hosed now.

When I launch Entourage, I get the error "Could not change to that identity. An unknown error (-5000) occurred." If I create a new identity and try to switch to it, I also get the same problem.

I have been unable to find a fix for this.

Suspecting it might be a permissions problem, I ran the permissions repair in Disk Utility. It didn't.

I ran the fix on this page, <http://macosx.com/tech-support/mac/office-2008-error-with-database/335965.html> but it didn't fix it.

/usr/bin/sudo /usr/sbin/chown -h -R root:admin "/Applications/Microsoft Office 2008" "/Library/Automator" "/Library/Fonts/Microsoft" "/Library/Application Support/Microsoft"

Unfortunately I have no idea what they did (I wasn't around when they were working on it) and I have no trust in letting them back into my system.

I'm wondering if anyone else has encountered the problem and might be able to give me some tips.