I have exactly the same problem, starting from around 2 days ago.

I have my Firewall in ZoneAlarm set to allow the LW port in UDP and TCP incoming and outgoing. I have clicked 'connect' in LW's 'File'. I've followed all the instructions that start with Tools - Options - Advanced - Listening Port - etc.

I've switched off my PeerGuardian2 to see if this was the problem. I've inserted the LimeWire port to be allowed through my Windows Firewall.

But the connectivity never completes, and an icon says LM is behind a Firewall.

I had LimeWire Pro operating beautifully until just 2 days ago. My Azureus works just fine. No connectivity problems, no firewall, no NAT problems.

I'm beginning to think that LimeWire has been sabotaged with a hidden virus or Rootkit or whatever.

I'm now looking for an alternative to LimeWire.

I've been through all the connectivity guides and it's come up 'zero'. If my Azureus was having the same problem, I would think that something's wrong within my own computer, but that's not so.

Goodbye LimeWire! When you people can get this bug fixed, I'll re-install. But I've had enough after two solid days trying to sort this out. I'm just going to simply switch over to torrents. Safer that way too.