Make sure that you're only using 1 software firewall & that it's configured properly
Firewall setup
Do you see the firewall icon (brick wall)?

go here with your browser & see if the test works
http://www3.limewire.com:6346

Read through the sticky (in red) at the top of the connections page. It has lots of helpful info & should be read before posting!!!!. Find the topic "Connection problems? Check here first".... that one's very good.

If you're still stuck, post back with your details
OS(Win XP etc)
LW & Java version (help > about LW & you'll see)
Firewall you're using
Modem/router brand & model
ISP
Connection type (DSL etc)
Where you connect from (home, school etc)
Are you sharing a connection with other computers
Is this your first try with LW