Ouch. They're a pain. See if any of these threads help...no guarantees but you never know
If you use the forum search to look for Tiscali, you'll find lots more threads from people having problems.
Some people have found changing ports helps. To do this, in LW go tools > options > advanced > firewall config. There you can change LW's listening port. Good ones to try are 49152 - 65535. Someone recently got connected after weeks of pain using port 139. Have a read of these...
Tiscali & Limewire can't connect between 5pm-11pm I have found a solution to getting Limewire to work with Tiscali