emergency mode

please help, i just bought my Aclass yesterday evening after passing my test on tuesday, and already I've discovered both rear doors won lock. the buttons stay down but wont lock... im so panickrd and dont know what to do, please help a girl out:cry::cry:

Last month my Mercedes ML 270cdi began driving only at low revs in emergency mode, when taken to my mechanic he had replaced the intake manifold. After about a week, I have been experiencing similar problems but the car now goes into this emergency mode intermittently. Some days the car is...