Lots of people have had probs with Tiscali lately.
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
(apologies if you've already read these!)

You could also see whether Java 1.6 makes any difference (it did for one person). Use the JRE offline installer here & remove your old Java versions before installing the new one.
http://java.sun.com/javase/downloads/index.jsp