Java not working on iMac

[videboi]

I have an iMac G5 and a PowerBook G4, and I am having a problem with my Java! I have a java based program that I want to install on my iMac, but when I try to install it, it just doesn't finish installing. And all of the java based things on the web don't work anymore. All of these things work on my powerbook which is OLD! All of these used to work on my iMac but they don't work anymore.

Please help!
Thank you!:D

[rfruth]

if only there was a search engine or something http://developer.apple.com/java/