getting started - where is the keyboard?

I just bought the new iMac but can't move on with the first set-up of the system as my wireless keyboard is not being recognised by the computer. The Mac just keeps sending codes; I enter them, press enter, the small green light blinks and then stops. The keyboard seems not to be the problem, as it works with my other mac.

Is there a possibility to move on with the instalation without a keyboard??

Thanks a lot!