OK OK NO NEED TO YELL ABOIT IT....LOL

being that its sat for a year it could be that the duel system is all gummed up on both the gas and lpg side.........ignition and injection is controlled by signals from the cam/crank signals somcould be a weak signal there at cranking. Also check and clean or replace the MAF sensor this plays a part in it also.

I would start by getting one fuel system to work/operate properly by either going thru the gas sytem and changing the filter and cleaning the injectors somehow. On the lpg side i would start by cleaning or rebuilding the NIKKI regulator and checking the injector holder and injector and cleaning any tar junk out.....