Do you have Java installed then? Try here:
java.com: Java + You Click on 'Do I have Java?' and see what they say.
... but don't click on any buttons that actually
do anything without being certain that it's
absolutely what you want!!
For me it said "you have Java version x, you should have version y, click to install". It was
completely and totally and utterly wrong, basically it didn't have a clue what it was wittering about.
I was deliberately running version x for a jolly good reason - I run applications on my machine that work with version x and do not work with version y. The Java industry has this weird belief that Java is backwards compatible - that installing a later version won't break stuff that's already on your machine - and it's just plain wrong.