I've had this trouble since I got the car for about half year ago. It's horribly easy to shift it into reverse when the car has stopped (either im stopping up for a red light or just started up the car).
Apparently it is supposed to be "difficult" or at least a little hard to get it into...
I just bought a 03 Celica gts and I am having shifting problems.
The car was shifting just fine until I couldn't shift into reverse (6 speed manual).
It feels as if it was blocked, and the 1st and 2nd gear have a lot of play.