Adlib nobody said to turn off anti-virus or firewalls. What is recommended is you configure your firewalls to allow LW full access. And depending on your anti-virus you may need to make exceptions but I don't know which av apps would require this.

User Guide: http://www.limewire.com/english/content/userguide.shtml

Check the other suggestions on this page & on page 1 of this thread. Why someone can't connect can be a mystery. I've a suspicion you haven't read all the hints on this page let alone any others. For the majority of users LW is easy to get going but for a %, they have some connection issues. Hope your java is up to date. Since you haven't provided much info, I can't suggest anything more.