Here's an AVSIM thread on the same issue:

http://forum.avsim.net/topic/224789-any-idea-of-the-cause-of-this-ctd/

Here's what you get if you Google it:

http://www.google.com/search?q=CTD+event+BEX&ie=utf-8&oe=utf-8&aq=t&rls=org.mozilla:en-US:official&client=firefox-a

You could also start or find a thread in a MS forum on it.

Bruce