Try uninstalling java from the add/remove programs, then d/load and install
Java Runtime Environment (JRE) 6u1(using the offline installer):
Java SE Downloads
Delete LW's preferences folder. Instructions in this thread(point 3):
Fixes for LimeWire
Now reinstall LW using the offline installer. Installing it will remove your current version.
LimeWire: The Official Site for the Fastest File Sharing Program on the Planet
If all that fails, uninstall java again and use this version.
Java Runtime Environment (JRE) 5.0 Update 11(using the offline installer):
Java SE Downloads - Previous Release - JDK 5
Let us know how you get on.