Well I was unable to make it crash after that. I tried moving emails between local and remote, (and in doing so I stumbled across the Outlook Express duplicate message issue, badly), I tried sending and receiving and moving files on the same account at the same time, hitting it with multiple users on a shared account, and everything else I could think of.
So far, I am becoming to believe it is one of two things;
a) Some kind of unexpected response from the ISP's SSL-enabled server that gums it up (because it crashes fairly consistently when it fails to deliver as described above), or
b) There is a user-detector that only makes it crash when a user is using it, which turns off when they go home and I slave away at night to try to figure out what the deal is.
Next step:
I made arrangements with another company to let me relay mail through their SMTP servers, no SSL and no restrictions. And I will grab the mail off the encrypted POP3 accounts with a regular client for the time being. Thus, no SSL. And I will see if the program is stable that way.
I'll let you know how it turns out. Thanks for your help.
--97T--
P.S. I've given up on running a mailing list using someone else's smtp and pop servers, so I'll start a more appropriately named thread for the crashing issue.
P.P.S> -- For those who find themselve chasing bugs, this might be a nice diversion: