Can you give us a total desciption of your set up: 1. OS version, 2. What firewalls you have, 3. ram, 4. HDD space available, 5. Connection type, 6. Modem & router brand name & model numbers, 7. Where are you trying to connect from (home, school, work, etc.)?
These details are vital if you want us to find out what your connection problem is.

You can try deleting your LW prefs folder called .limewire & found here:
Windows: C:/Documents And Settings/your_username/.limewire
OS X: /Users/your_username/Library/Preferences/LimeWire