96 Corsica p1780 code?? HELP!

Hey my wife's 96 corsica 3.1 auto is throwing a p1780 code...the guy that pulled the code didn't know what it meant. in searching the interent is said that p1780 is a "park/Neutral pos [PNP] switch circ" anybody know if this is correct and what it means and needs to be done? I need to get this fixed ASAP.
Thanks for your help!!