Try deleting your LW Preferences folder whilst LW is closed; instructions here: Fixes for Limewire

If that doesn't work, I wonder if it's an issue with your modem/router.

Can you give us a total desciption of your set up:
1. OS version? (eg: Windows 98)
2. What firewalls you have?
3. How much ram?
4. Hard Disk space available?
5. Connection type? (eg: dialup, broadband, cable, etc.)
6. Modem & router brand name & model numbers?
7. Where are you trying to connect from (home, school, work, etc.)?
8. What version of Limewire (LW) & Java do you have? (Go to LW's menu Help>About LW...) Will show both LW & Java version.
9. Who is your isp provider?

The latest beta might be an answer but we might be better to see if the problem is something else such as your modem having issues with LW.