Dell 962 Printer Jam

The Dell 962 printer manual instructs me how to clear a paper jam.  However the paper jams every time a print is commanded, thus a print cannot be made.  I need advice on how to prevent a paper jam.  I use the correct paper, properly installed in the tray and the printer is level.  The jam occurs when the paper has reached the final set of feed rollers.  All the rollers are positioned correctly (previously one roller had cocked, causing a jam, which I fixed by positioning the roller correctly).  Now the jam persists and it appears all rollers are correctly positioned.  When I removed the two gangs of final feed rollers a jam still occurred which indicated that the final feed rollers are not the problem.  The initial feed out of the paper tray appears correct. Please advise of possible discrepancies which might be the cause of the jams.

From Brian Young