problems with gearbox

Hello I wanted to ask you maybe you know what may be it was a fault with crankshaft sensor so I replaced later it was telling me that speed sensor is bad and now it came up with engine light on and I cant start it because the car show that it is in Drive position but it is still in Parking. When I checked on Drive partronic it got stuck in 4 gear anyone had that kind of problem cos I dont know what to do know should I take to main dealer? It is skoda superb 2.5 td v6 2007