This very early macbook pro I salvaged (A1150) has two minor niggles.
Firstly, even though the keyboard seems to work fine this message appears at every boot
Secondly, The mouse cursor acceleration is super sensitive despite setting it to its slowest setting.
Here is the about this computer
About the error message, I think this is a miss-configuration between the x.org and your keyboard layout. I would try to force your keyboard layout once again + reboot to insure that correct values are set up. You can also search inside dconf-editor for a solution :