Error 18500 in Entourage

I set up Entourage to get mail from an exchange account from work. Everything works fine except a continuous error I receive.

Could not synchronize record: xxxxx to Exchange server: xxx Mail

Use a search engine to look for that error code.

Running short on time, or I'd try it myself.

I already have but it points to calendar problems. The errors I get are messages and so far there is not much out there for an explanation

Did a google search:
Let me google that for you

According to the bulk of those results, the problem would seem to be on the Exchange Server side.
Have your employer make sure that the Exchange Server is up to date with patches and what not.