Hello,
I removed your email address, as we want to encourage participation here in the forums at DaniWeb. Others may have the same issue that you have, and it would be beneficial for them to see it too. Please keep the conversations here.
Your keyboard is working in OS 9, but not in X. That is interesting. I think there were firmware updates to the G4, but do not remember to what models they applied to, and what they fixed. You might wish to search Apple's website for an article concerning that. Search on your specific G4 model.
It is also possible that OS X needs to know more about your Keyboard. Get into the System Preferences, and into the Keyboard control panel. See if you can specify a keyboard in there, and get it to work.
Let us know what you find!
Christian