HELP!!

Okay, I have just ran through half of my duracotten 98 with only two coming out of the printer without jamming. I have tried the plain paper setting, the heavy setting and the transparancy setting. Went through about 20 sheets and not having any luck. Has anyone tried the duracotten on a Lexmark and if so what were your settings? The temperature on the fuser is only 338 and we have tried it cold and still it jammed. Help Help Help!!!
Thanks
Mystic