Tweakermonkey,
I just fixed a problem with outgoing mail, and the problem wasn't Avast, it was the ISP changing the required settings. If your ISP is one of those gobbled up by Earthlink, they have changed the server settings.
On your post, you show your incoming server IP is the same as your outgoing server name, and I believe this may be incorrect. If you're using Earthlink, go to their support.earthlink.net page and select 'Email problems' and follow one of the links to check your requirements for the specific service you started with. (smtpauth.earthlink.net may work in the outgoing server name line, if you fell like gambling)
If you're not in the Earthlink empire, well, good luck.