whatever you do, dont force the door.
the tape has probably wrapped round the capstan, or it may just be a slack drive belt on the mech.
unplug the set and remove the back. look for a metal capstan flywheel on the tape deck mech.rotate anticlockwise a few times, this should loosen things up a bit. if in doubt take it to a tech. it is cheaper to do that than repairing it if you force it.
romko
January 2007