Before you install LW it's always best to install the latest version of Java: Java 1.5 (take the JRE)
Also go to Control Panel then Add/Remove Programs & click on Limewire on the Change/Remove button & it comes up with options and one of them is Repair. Try this.

Make sure your firewalls are configured to allow both LW & Java full access: http://www.limewire.com/english/content/firewalls.shtml

To delete LW's Preferences folder (yes you will need to reset your options), look for .limewire found here: C:/Documents And Settings/your_username/.limewire (BUT whilst LW is closed!)
For Windows 98 / ME: Your .limewire folder is in "C:\My Documents"

One other trick is Right-clicking the Limewire icon and going to properties and change compatability setting to Windows 2000