I just downloaded Lab Tick, and it says my PB doesn't have a Backlit keyboard, I thought they all did?
Looking back at some of your previous posts, it appears that you have a 15" 1.25 GHz PB...is that right? That model did come with the backlit keyboard, so it should work. (The 1.0 GHz model released at the same time did not have the backlit keyboard.) Hmm...
If you go to System Preferences --> Keyboard & Mouse --> Keyboard, do you have the "Illuminate keyboard in low light conditions" check box available?
Has the keyboard been replaced at any point? Has the backlight ever worked for you?
You're also not the only one with this issue, if that makes you feel any better.Unfortunately no answers though.