IMHO, you've let this car set around too long or moisture has goten into the clutch area & rusted it (discs have steel in their facings). Un-sticking a frozen clutch disc is tricky 'cause it can be stuck on either side- to the flywheel or clutch cover- and you can only access the flywheel side thru the small hole in the bellhousing. Complicating this is the stock Pantera's clutch disengagement distance of maybe 0.040". A long slim blade of some type may be able to be progressively tapped in thru the access hole while a helper stands on the clutch to lessen the pressure, but I don't hold out much hope; I expect the ZF will have to be pulled to fix this. If its truely stuck, trying to free it with the engine running could rip the facing off the disc. And since the car obviously sat undriven for some time, have you checked to see how many brake pistons are also stuck? IMHO, this car needs to go to a Pantera-savvy shop for remedial work. Good luck with your next purchase- J Deryke