Mail (IMAP)hangs on copying sent message or RSS?

Question

Mail has been working well using an ancient AOL account via IMAP,but now hangs if I select one or more sent emails (or RSS messages) and use the menu to copy them. A force quit is required.
If instead I try to copy several incoming messages, it opens a window indicating copying from server and the progress bar proceeds extremely to completion but it is not possible to paste the result (if it exists) anywhere (e.g., to a mailbox on my mac).
Otherwise mail is working in that incoming messages appear normally and outgoing messages proceed as before.
The copy failures have occurred since a couple of events/changes that may or may not have caused this:
1. Installed the last security update 2008-7(?)
2.a later system hang/near KP a couple of days ago (upper half inch of the screen went dark grey and everything froze, as if the KP screen was starting to show but couldn't even get that far.
I've since run Disk utility for permissions, then Applejack, then Diskwarrior with no effect on the situation. I rebuilt the mailboxes that were the desired sources and the target mailboxes also with no effect. I haven't tried anything like discarding mail plists.
Thanks for any suggestions on diagnosis or cure.

Answer 1

Ernie,
I don't know about Tristan but I can say;
1- Previously left the SMTP servers I have (about 7 of them, mostly fully authenticated) using the 'typical ports' setting which presumably cycles between 25, 465 and 587.
2- I have had cases where 5 messages have failed to send but only 2 of them appear in the 'outbox'. In that case mail.app was showing as 'Sending' but I was unable to see what it was sending and which smtp server it was trying to use. There was no way to cancel it either (the activity window was no help).
3- I don't use 'Use this Server Only', I typically try every server I have.
The problem is that hotel ISPs typically even try to intercept SMTP over SSL, leading to Mail.app getting royally confused.
Is there any way I can get some better diagnostics on what's really happening here? I usually find that mail.app works OK until it starts trying to send a mail, so my feeling is that I should be concentrating on the SMTP stuff. I have now switched over to using port 587 (for SMTP over SSL) only in the vain hope that the hotel ISPs aren't watching that port- my suspicion is that mail.app is poking port 25 first, getting the intercepted server and then trying to use authenticated SMTP to that (spoofed) server and getting confused- that's born out by the certificate failures I often see when in hotels.
Thanks.