Quote from DAV:
TWS broswer version 877.2 is now available. All known crashing problems in previous 877 are fixed.
Strangely enough, I got crashing problems on order entry for the first time with 877.2. I never had a problem in 877.1. (And I clicked the send report button).
Actually upon further experimentation, it looks like if I manufacture a pink out (by pulling the network cable) and it reconnects, it crashes on the next attempt at order entry. Something along these lines. Hopefully the report that TWS sent will be more informative as I'm leaving for the day and won't be experimenting further!