Try leaving the $WAGLOBAL_Email_Server setting blank:
$WAGLOBAL_Email_Server = "" ;
For many (most?) hosts, this is all that is required. Try that and post back if you still have problems.
Your friends over here at WebAssist! These Dreamweaver extensions will assist you in building unlimited, custom websites.
These out-of-the-box solutions provide you proven, tested applications that can be up and running now. Build a store, a gallery, or a web-based email solution.