Dell Printer 2155cdn MFP Error code 024-910

I'm getting a 024-910 error on a Dell 2155cdn MFP

It prints test pages fine, (dozens at a time) with no error. 

I print from the network and the first one or two pages are OK then it kicks out this error.  

I pull the tray out a couple of inches and push it back in- a few more page (1 to 4) print then I get the error again.   

I've tried a different paper tray, (from a working unit) and the error stays with the printer.  I've cleaned the "d" pick roller.  

I have not updated the firmware yet -why am I posting before I do that I don't know :)