I'm not sure if you are talking about headlights, angel eyes or fog lights, but I bought a set of xenon angel eye upgrades from them and mine do throw an error code.
My car is an '06 e90. I got them in Dec '07 and just got around to installing them last week. When I contacted them they told me they cannot be returned since I have had them for more than 45 days. All I can get is a store credit.