What does error code 5100

Its is trick..If its more then two pages print, printer grabs second page even first page in duplex unit., here its confusion. Check with simplex single print, see any paper mismatch error? or printer throwing paper in output bin after successful print?. No.. check fuser out sensor or paper out roller.
Print only two pages matter in duplex, check where paper struck? if paper our roller not grabbing paper back properly in time (slipping while grabbing back) gets jam error.
Always ensure that select proper paper size in printer.Other than this it may major issue, need technical knowledge..& possibilities are less to judge the exact problem..
Keep update us to resolve the issue.

check between the rollers there will be small bits of paper jammed in that is the reason.

remove the small, or scratch into pieces inside the duplex to clear the paper jam.

See page 75 of the attached user manual on how to remove a duplex paper jam. If you can't find a paper jam in the duplexer, simply remove the duplex assembly (power off the printer, then power on) and see if that resolves your issue.

(The printer will operate just fine without the duplex assy. installed)
Okidata C9650 User Manual

HI ayyasamyr:
This your problem.
13.10 PAPER JAM The event log message for a paper-delay jam in the duplexer is 13.10.
1. Check the duplexer and the rear area of the printer for obstructions or damage.
2. Check PS1701 and PS1703 in the duplexer for correct operation. Replace the
duplexer if a sensor is defective.

Hope this helps

if you are gettiing a 201 error without any paper in the printer you will need change the main motor drive if it fails to initialize this is the error that will show up and there is no other way to reset it

1. Take out paper tray 1.
2. Remove any jammed sheets of paper you find there.
3. Once you have done this, reinstall the paper tray and try printing again.
   Note: You may receive a message informing you that another sheet of paper is jammed elsewhere in the printer. If so, please open the front door and remove the toner cartridge. Also open the rear door of the printer (and the duplex option if a duplex unit is installed). Remove any and all jammed sheets of paper you find. Then try printing again.
4. If the printer jams again with a 241 Paper Jam error message, look to see if it has tried to feed a sheet of paper out of the tray.
   

Hope this helps....
Explanation of the paper jam message

A 241.09 Paper Jam message indicates that the printer thinks a sheet of paper has jammed at the front of the printer. The jammed sheet of paper is most likely to be found in one of the paper trays or under the toner cartridge.
NOTE: If you select Show areas on the operator panel, you can view one or more images to help you locate and clear the jam.

Clearing the jam
To resolve the paper jam message, you must first clear the entire paper path. To access the jam area, you will need to open one or more of the paper trays. Follow the steps in the table below to help you locate and clear the jam.
Step Action Image 1 Open the printer paper tray (tray 1), and remove any jammed media you find there. 2 Open the front cover and remove the toner cartridge. Examine the area inside the printer and remove any jammed media you find there. 3 If you have a duplex option installed, also remove the duplex access tray and remove any jammed media you find there. 4 If you were printing from an optional paper tray, such as tray 2 or tray 3, open any optional trays, starting at the top, and remove any jammed media. Pull the print media either up or down. If it does not pull easily one way, try the other way 5 If you are printing from an optional 2000-sheet feeder, open the front door. Press the elevator button (A) to lower the tray. Remove any partially fed media from the feeder.
NOTE: Make sure the stack of print media is straight and pushed all of the way into the feeder. Incorrectly loaded paper is the most common cause of paper jams from a 2000-sheet feeder option.

For a larger image, click here. 6 Finally, reinstall all of the paper trays and press the button to try printing again.
NOTE: You may receive a different paper jam message informing you that another sheet of paper is jammed elsewhere in the printer. If this occurs, the error code will indicate the location. Click here for a diagram showing the error code locations. The paper path will vary, depending on the paper source and number of paper feed options installed.
Remove any jammed sheets of paper you find and try printing again.

your getting a 383 paper jam, find paper in two different places.
See if it's a duplex related problem. print single sided documents, if that works, try printing two sided documents (it'll be the duplexer) if it only fails while printing duplex.

Also, check the back door. Make sure the back exit tray is closed all the way.

You can also have a paper jam in the duplex unit (open the front door), the duplex unit slides out the front. You can easily remove the duplex unit and run the printer without it.

Were you doing duplex? take out the duplex and look in side and UNDER it