Topic: rme ff800 left right channel problem

Hi,
I have the following problem: I use a RME FF800 on my IMac and Cubase 6, when I mix into Cubase I set the pan of channel left and right (for example drum overhead). When I make the mix down of the track it sounds with left and right channels in good way when the RME is working. If I listen the song in another pc or in the car, my left and right channels are inverted. I use out 1 left and out 2 right on the rme. Really I can't understand how is possible, in Cubase is all ok and the outputs are correctly assigned.
Could someone help me?
Thank a lot!