I sorry to be the bringer of sad news... but there is a TSB(Technical Service Bulletin) that BMW put out in july 2006 pointing to CODE 048:
Unfortunately, a torque converter replacement is the only remedy if the shaft seal has deteriorated.
What you can do:
1)have them clear the light a few times. It just might just been a glitch. With some luck it might go away.
2) measure out & examine the tranny fluid. if dirty, try a flush and replace fluid to manufacturer's specs.
that is certainly worth taking a chance on instead of footing the bill for a new TC