When you enabled Chat in the settings did you press the Apply button? Let's also hope you're not firewalled. See tips here How to Direct Connect, Browse & Chat

Do this test: Bug Report instructions & sample image Is the result True/False? If False then you have a firewall issue. Configure your firewall for full LW access here: http://www.limewire.com/english/content/firewalls.shtml
And only use one firewall. 2 can interfere with each other.

Almost forgot, you can often only chat with other people who have chat enabled! This is not necessarily always the case but. Also other p2p programs are not always easy to chat to. So set chat column up by righ-clicking the top of the column bar in downld, search results & upld windows.