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. What graphics card brand & model & driver version do you have?

It might be wise to uninstall all your Java & re-install using 1.4.2 initially to see if this works better. But install Java from your comp. not over the net. You can find links here: Fixes for Limewire
Also change your LW compatibility to win 2k.