[Dovecot] IMAP EXPUNGE disconnect/box hang - Fedora Core 2, Squirrelmail and Evolution

[Schettino, John Charles]

I'm a bit befuddled by this behavior. I've been using dovecot for close to a year, and recently the Fedora Core 2 Update: dovecot 0.99.14-1.1.fc2.rf.i386 build came in via yum. Since then I occasionally get this EXPUNGE disconnect error. When the error hits, the box does not crash but I can no longer log in*, nor start any new processes. I happen to have gkrellm running and I see a slow but steady climb in the # of processess. The only way to recover the box is to do a hard reset, as I cannot log in, nor su - to do a shutdown. In one case I happened to have a root shell open, and I still could not do a shutdown. 
Any ideas as to what I should do with this? As long as I don't expung everything is fine, but when I do expunge (move something or a filter runs in squirrelmail, or Action/Expunge in Evolution) sometimes it works fine, sometimes I get this error and a weird zombie state. It was all rock solid before this new version. Suggestions welcome - I don't seem to be getting any logging when it goes bad, perhaps I can up the log level? 

* If I attempt to ssh in, I can enter login and passwd, but it then just hangs. If I was already logged in somewhere (xterm or ssh) su - prompts for password, then after entering pw it also hangs. Web server responds if I fetch a static page, but mrtg/rrd graphs don't ever load (since they need to be generated, and for some reason no new processess can be spawned)