You could try turning the McAfee Firewall off for a little while, just to check if it's in fact the root of your problem. I have never tried McAffe myself so I can't really be of much help there.

Since you use Dial-Up and there is a brickwall in Limewire, it's most likely one your your firewalls blocking access to the network.

Another thing you could try is in Limewire going to Tools-->Options-->Advanced-->Firewall Config and choose manual Portforward. Then enter 6346 in that box and also in the box for the Listening port number on the same page.

Also try disconnecting and reconnecting Limewire after you give it time to settle down. Maybe even cancel all pending downloads.