Sounds like you've got it the wrong way round bud. The nuts should loosen the same way the motor spins. If you hold the nut and spin the motor, the nuts should tighten.
I'm not sure. Can anyone confirm.
Looking down from the top with the front away from me.
Bottom right :- CW Motor Thread (silver nut).
Bottom left :- CCW Motor Thread (black nut).
Front right :- CCW Motor Thread (black nut).
Front left :- CW Motor Thread (silver nut).
edit:- seems the rotation appears to refer to the direction the nut turns when tightening, not motor rotation...never noticed that. Gutted.