spiro,
I hate to tell you this, but you are not the first to have trouble with the configuration of Avast when tiscali is used.
I am presently working on a solution but am not sure how soon it will be figured out.
For some unknown reason, Avast does not seem to like the configuration of smtp.tiscali.be or whatever, nor does it run with pop3.tiscali.com
I have sent a requet to tiscali support in the hopes that they will work with me on a solution.
I will keep every tiscali user updated.
techie