It sounds to be an isp issue to me. If you suddenly can't connect to someone then it suggests isp shaping for p2p programs.

Let's check:
Do this test: Bug Report instructions & sample image Is the result True/False?

What is the full name of ntl?

Try deleting your LW Preferences folder whilst LW is closed; instructions here: Point #2 & 3 in Fixes for Limewire (sample image included.) Do you have same problems after doing this?

If still no good, try changing your port from 6346 to one between (49152 - 65535) or 80. See if that makes a difference. You'd need to go to LW's menu bar, Tools>Options>Advanced>Firewalls & change the port, press apply. Reconnect or re-open LW. See if that makes any difference.