Odd Entourage X Crash Problem and Work-around

I was working with a client last week who was having constant crashes whenever their MS Office v.X version of Entourage performed a mail check. After poking around in the Microsoft Support Knowledgebase,I came across this tech note.

Cannot download e-mail in Entourage X for Mac

The problem resides with the Junk Mail Filter in Entourage. Disabling the filter allows the mail to be received. Luckily, this client doesn't get a lot of junk mail, so this was ok, but those people who use the Junk Mail Filter extensively would be left without any way to manage this.

While this work-around did solve the problem, it offers no explanation of why the problem occurs in the first place. Entourage 2004 seems to have fixed this problem, as well.