jonzie,
I don't give up either. I came across this article which might help:
"Certain ISPs (as Netcom, Earthlink, AOL and others) will not let you send email via smtp-roam. They will silently force you to use their own SMTP server. This prevents you from being able to send email. If your connection times out, or otherwise fails when you attempt to send email , you may need to make a small tweak to your email program. Most programs let you switch from port 25, through which your ISP can hijack your SMTP server, to port 465, which will prevent this from happening"
It is worth trying
Also, I would like you to go into the Internet Mail module of the On Access Protection. Go to Customize and disable "Scan outgoing mail under the SMTP tab.
Try to send email again. I want to try and localize the problem area if it is indeed Avast.
Techie