stability system track disabled

I would have a hard time connecting the stalling condition to the rear brake repair. Is the engine stalling when coming to a stop sign or when making slow turns? If that is the case it could be due to a low idle condition caused by a dirty throttle body. The correction for this would be to clean the throttle body or have it cleaned. There may also be a fault codes stored in the ABS control module related to the stability system. If there are no codes stored I would suggest concentrating on the stalling issue and once that is corrected see what happens with the stability message.