I had the same problem. The problem was with the wires for the airbag under the passenger seat. I believe this is a comman problem and can be easily fixed. The wires need pushing into the white connector, they may have come loose when the seat is pushed forward. The same thing may have happenned to the drivers seat. Just give the wires a good push in to make sure there is contact. A permanent solution if the wires keep coming loose, is to hardwire in ie no connector or solder the wires in place.
Ryan Hayward, January 2007