This has been going on for a week off and on... I know it's nothing to do with my ISP. Today I've been downloading music with no problem, and then... all the connections (the ultrapeers) drop. My green bars turn red and I get a message to say that I have no connection. Yet seconds earlier, everything was working fine.

Could it be an ISP problem? I never had this problem with my previous version of LW. I'm on 4.12.3. I can never stay connected to any one ultrapeer for more than 10 minutes... then they all go and I just get a load of ultrapeers connecting, and they just don't manage it...