I have a problem with my DFP where the gear stick is stuck in the up-shift position, according to the game controller software on my PC. The stick still clicks up and down like normal but this problem obviously causes problems when trying to play games!
Open it up (easy to do) and see if the lever isn't contacting what it should. You may want to try manually activating its buttons while its on and seeing if it works that way. Just watch what you touch (the electric motor is probably the only danger) while it is plugged in.