Duplicate messages using Lycos Live and Outlook Express 6

I might be missing something obvious, but whenever I send a message through Outlook Express from my Lycos account, two messages appear in the recipients' mailbox, although I only get one message in my sent folder.

Does anyone know of a way round this, or what I might be doing wrong?

Does your Lycos account support POP3/SMTP, or are you using some local proxy to send/receive via Outlook Express?

Not sure of one for Lycos, but an example of what I mean would be YahooPops! or Hotmail Popper.