Ahem; anyway...
"Pure Virtual Function Call: about to throw exception."
I got this for the first time while using Rhapsody.4 (after the 3rd time DL'ing it due to frequent errors; the most recent was telling me every other song was corrupt.) I cleaned Helix and DRM files, checked for updates, and DL'd the most recent IE security update. About 2 minutes after running Rhapsody again I got the error.
I'm finding it very hard to find anything about this that isn't in pure computer-tech jargon.