That's because a driver hasn't been writen for it. Because of that, piKey can not understand you keyboard. Personally, maybe you should get a refund and keep you eyes peeled for other cheap, but very good IR keyboards.
"Targus" is a good bet. It's cheap, portable and I feel... works the best!
Unless you code, it'll be very unlikely that you keyboard brand will find a place in the PSPIR keyboard library and work with piKey.
Sorry to disapoint.

Like I said, Targus is where i'll spend my money.