LimeWire is independent of operating system. It relies solely on the Java Virtual Machine.
If you haven't already done so - you could/should download the latest Java VM (Java Runtime Environment - JRE) from the following link:
http://java.sun.com/j2se/1.4/download.html
After installing the latest version of Java you may need to re-install LimeWire (I'm not sure if it will pick up the latest java without a re-install). Since you are having problems, a re-install of LimeWire is a good idea anyway.
There are plenty of people using LimeWire under XP without a problem - so you need to look closely at your system to find what is wrong with your system.
Read the forums and see if any of the problems described match what you are seeing - the solutions given there may well help you. There are other XP users who have had problems - so you should find something that relates to you without much too much effort.
Mark
Mark