i figured out the problem, it was the signal from the wireless keyboard to the reciever. Apprently the signal was not turned on properly, after pressing the connect button the wireless keyboard it worked normal again.
Thanks Nednerb. Your solution works for iMacs. I did all updates for the IntelllType Pro and yet I was getting wrong Key-characters. I tried your solution and wuaaah, it worked like charm. kudos nednerb.