Have you installed Java to somewhere other than it's default location?
I don't know what you're running but the application might be looking for the java_home value to be set. This guide
will guide you setting the property. You should be able to point it at the directory with your java install (which is probably the runtime environment - JRE but it should still work)
Alternatively go and install the development kit
. It's total overkill if you are just running Java but it may solve your problem.