Race Face Crank/Chainring Compatibility
I had this problem with a pair of Race Face Cadence cranks (road version).  I think Race Face does this to force you into buying their chain rings.  I am sure there is some "engineering" argument why their rings are more compatible with their cranks, but frankly their rings are only so-so (my opinion).  So far every brand I have tried has this conflict as they use a square profile on the ring/crank interface, not a square with rounded corners.

To get around this simply Dremel or file off the offending material on the chain ring so it fits flush on the cranks.  Then pedal off (or glide downhill in you case) into the sunset with a smile on your face.  I have done this with a some FSA rings and have put 5000 km into them with no ill effects.

Take my anecdotal experience for what it is worth.