Hi Alexmeme, I'm not an expert but I'm going to tell you what I did when I had your problem, If it works let me know... and as of now I haven't had any more problems.
First I went to the Firewall settings (Windows firewall, that is) and added as an exception my Limewire.
Then I went to the antivirus settins (In my case avast!) and did the same thing, and after that I restarted my computer.
- All this was done following directions from one on the threads from this site, but I don't remember which, and that alone was supposed to solve my problem -
Still however I got the wall in front of my world, so I went to another thread and did what it said, which was: go to Limewire Tools/Options/Advanced/Firewall config there you have two options Listening ports and Router Configuration. On Listening ports you shoud have a number, and on Router configuration you should have checked the option Use UPnP so, check the option Manual Port Forward and write there the same number from the 'Listen on Port section'.
Restart your limewire and see if it helped...