Who is your ISP? Sounds like your ISP isn't allowing you to use p2p during their peak hours... a few do this.

You could try changing the port that LW uses, but if it's your ISP at fault, there's no guarantee it will help. In LW go tools > options > advanced > firewall. Change LW's listening port to 65000 (you can also try other ports in the range of 49152 - 65535) > apply > ok.
If you have port forwarding set up or a specific port number allowed through a firewall, you'll need to change the port forwarded/allowed to LW's new listening port