Win XP running under the Boinc Admin account settings. McCaffee is running, but has BOINC in the whitelist. No other security programs running (that are visible anyway). I've checked for inimical processes without finding any. This is the first time I've had this particular problem.

Found that some tasks from another project were also smacked with this error as well as a no memory error (beats me how 2 Gigs goes up in smoke, but...). The only other thing happening was that my internet connection was faulty (seems I'm EOL...yay me). As this seems to be a problem locally, I don't know how that would cause this either - unless the core shuts down when it expects a clear connection and can't find it. I've never heard about that in the BOINC forums, but I've been known to miss things.

That's not 100% correct.

BOINC communicates with the science application using shared memory. Things that can cause the error include problems with the science application, extended CPU starvation due to other processes, and conflicts with security software. In addition to these known causes, in some cases the cause remains unknown.

Remember, this message alone isn't an error. It is only a problem if it happens repeatedly.

Lawrence is right, though - rebooting can solve the problem in some cases.