Transmission Gear Indicator problems of the 2002 BMW M3

On November 2nd, 2005, at 6:30 p. M. , my family got into the M3. That included my wife in front, and three daughters in the back. We were on the way to meet my father for dinner. We had planned to take the 60 freeway westbound, of which the on ramp is off a street called chino hills parkway. To our shock, the freeway was jammed like a parking lot, so we proceed to make a u-turn to take an alternate side road. Travelling southbound on chino hills parkway at about 25 to 30 mph in 2nd gear, the smg gear indicator goes to "0". I do not recall shifting at all, so I just proceed to move the gear lever to put it back in gear. It does not change, reamins at "0", and since my foot is still on the gas pedal, I just hear the revs of the engine while noticing I have no power to move forward. Thankfully, we were on a slight downward slope, so I was able to safely coast to a stop by the right side of the road. The first thing I notice is the yellow gear-shaped transmission light has come on. I proceed to shut the car off, thinking a restart would correct the situation. I try shifting into gear, but it remains at "0". Before I restart the second time, I pop the hood open, and go out to close it, having heard that sometimes the smg pump acts funny if the hood is not closed. I'm still unable to shift. I turn off the engine, wait a few minutes. This time, the engine doesn't even start! this happened two more time. Finally, on the sixth restart, the engine comes alive, and I am able to shift into gear. The yellow transmission light is still on, but we made it home since this all happened about 3 miles from home. The car has been flatbedded to the dealership.