There is a seller help on amazon.
I recall this on ipods at one point. I had come across some on clearance at a local retailer in white, black and pink... I could sell the black and pink, could not sell the white as it was restricted..
The answer then was that they had too many other sellers, they had possible fraud with that item in teh past and therefore were restricting to basically larger volume sellers. I was pissed but still have probably not sold 50 items on amazon at the time, so I returned the white ones and lived with it.
Either contact them for pre approval on that item, Which if I remember requires a stand alone website to be put up as a retailer of restricted items. Basically you have to be a real vendor.