Evolution does not communicate

Hello.

Sick of ThunderBird's slowness and bugginess, I'm trying other clients 
and this time it's Evolution.

I installed it and configured an IMAP account, but at startup I get the 
message "Scanning folders in IMAP server...", a spinning wheel and 
that's all; after a while "Socket I/O timeout" appears.
tcpdump shows no network traffic.

Is something else needed in order to make it work?
Some service that needs configuring?

Notice I use XFCE, not GNOME. Is this a supported setup?

  bye & Thanks
	av.