I had a similar problem. Here's a link to my post: Transmission won't engage :-(
According to the tech at the dealership, the tranny sensed the fluid flow was restricted by the dislodged filter and the computer shut my tranny down to prevent damage. Sounds similar to your issue. If your dealership hasn't already done so, they should check to see if the transmission fluid filter is installed correctly. If it is, the problem could possibly be restricted fluid flow/low fluid pressure, or even a faulty sensor.