This would probably be the 'fuel lock' for the gas system (small black box-about 4cm by 4cm with 3 or 4 wires attached to the bottom of it.) If you look where the wires go in there should be a small red LED. Try starting the car and have someone watch the LED, if it doesn't light up, that's what the problem is. They're about $25 and very easy to replace, just unscrew it, take out the wires and put the new one on and plug the wires back in.
(of course I mean start the car on gas...)