So you cannot get into drive?
I heard of the problem once, something about the rear breaklight fuse and if
its blown you cannot put into drive?
Also you have to put your foot on the break pedal before you can put into gear
maybe the brake pedal switch is not working?
There is a solenoid that keeps the shifter in park that could be acting up also
found this file on the net, might help you out.
Let us know how it works out, good luck.