Try posting more specific info on setup first. Please try to answer all the questions.
1. What's your connection like - do you have any green bars at all?
Is there a brick wall in front of world ?
2. Do this test & see if it works. What does it say ?
http://www3.limewire.com:6346
3. What are your details
OS ? (Win XP, Mac OSX etc.)
How much free harddiskspace ?
How much RAM ?
LW & Java version ? (In Limewire press Help>about LW & you'll see)
What Firewall you're using ?
Modem/router brand & model ?
Are you using portforwarding, UPnP or nothing ? (Tools>Options>Advanced>Firewall Config)
What is your listening port ? (Same as above)
ISP (Internet Service Provider) ?
Connection type ? (modem, DSL etc) + Speed Up/Down if you know
Where you connect from (home, school etc)
Are you sharing a connection with other computers
Has Limewire ever worked for you ? If so how long have you been using it ?
Have you tried using any other P2P apps & if so, do you have the same problems ?
Also include any attempts to fix this. It helps people rule things out