Duplex printing with a Lexmark C500n laser printer.

I may be spinning my wheels here but here goes. I just bought a Lexmark C500n laser printer. I am trying to duplex print on 67 lb card stock. It goes through the printer fine on the first pass but when I put the card stock back in the tray the printer gives me an error message "jam rear" every time. I pull out the tray and make sure there are no errant sheets of paper in there, put the tray back in and get the same message. If I load plain paper in there or new card stock the print process works. I tried setting the media type to thick 1 and thick 2 but that did not help. Is there a solution to this problem or am I out of luck?

PS I did try contacting Lexmark but that was 3 days ago and I have not heard from them.

 

Try using regular paper. If regular paper don't work, the stock gets too moist or is unable to print duplex. If it does work, maybe the 67 # is too heavy a stock to print (a second time).
Does Lexmark website have any troubleshooting links?

 

Lexmark printers... aren't very good. Mine stinks big time but my question is do you only put one sheet of paper in the printer at a time? When the one prints do you immediatly put in another sheet?

 

Any help:
http://support.lexmark.com/cgi-perl/knowledgebase.cgi
Does the duplex printing work on a thinner paper/form, etc?
Maybe you can print on a different form?
If you really want to print on the 67 lb card stock, maybe you can go to your local computer store & try printing on THEIR printer, with the promise of buying the printer that passes the test?
Hope this helps, as I am out of ideas......