My brake/DSC lights keep coming on as well. I checked the codes and it is one of the pressure switches. From digging I read that they are not cheap, but its best to change both of them when everything is all apart. I have not gotten around to it because it is not happening often enough for me to worry about it (it goes away after I start the car again).
I will definitely be taking my car to the local BMW indy specialist when the lights stay on pretty consistently. The Dealer would just charge way too much.
2005 BMW 330i ZHP 6MT. Built 11-19-04. Bought 4-2012.
Stock: Nav, leather, PDC, Xenon
Added by me: OEM Alarm, OEM heated seats, OEM aux kit, OEM Bluetooth, intravee, M3 strut brace, BMW Performance Intake, Nappa leather arm rest, updated LCM (triple blink, euro hazards, trifecta lighting, 3 stage brakes), temp gauge