Josein-

Do you have SP2 for windows xp?
If so, have you made sure that limewire is allowed through your firewall?
What version limewire do you have? Not sure what version you get when you call by phone with 2.50. You might want to make sure it's the official version that you get when you go to www.limewire.com If you get basic, it's free. No phone call or code needed.