The reason I asked where you connect from is because a school or office might've started blocking access to p2p. And an appartment complex might have added/updated a firewall associated with it's internet connection.

Did you use any of the fixes within the thread I linked to yesterday? If none of those things worked, try port forwarding for your router.The instructions are here.
Port Forwarding for the Linksys WRT54GS

Don't forget to set up a static IP address first. LW's listening port, port in the 'manual port forward' box & port forwarded within router setup should all be the same number.