ABS, DSC,and BRake lights on and Ft. left brake dragging

Hi guys, I know this question has been asked many times but maybe someone out there can answer my questions. I bought a '99 540iT a month ago but have only been able to drive it for 2 weeks because my DSC, ABS, and BRAKE light comes on. I drove it for one week with the lights going on and off and now I can't drive it anymore because my Ft. left brake drags, gets hot and has warped the rotor and makes the car impossible to drive more then a couple of miles because it starts to shimmy soooo bad. My Bentley says stuck caliper, faulty master cylinder, or traction control system faulty.... read codes. I would like to think that it is a trac and all the problems that happened in 3 weeks are related, but My peake DIS reader and my generic OBDII reader show no codes! Has anyone had this scenario happen? I have read lot of people replacing the wheel sensors(which I don't think could be the problem) and ABS pump but I don't want to destroy another set of rotors guessing. Thanks in advance.