Sometimes my paper just gets stuck in the paper tray. What I can recommend is to change your paper and try different jam-free papers. Some type of papers tend to cause paper jam more than the others.
"Dear Sir(s), I just want to thank you for the "Easy Refill Kit" which I ordered for my Desk Jet 610. It was a breeze to use and the resulting quality of the "print" was absolutely perfect. Thanks again for a great product!" (Don D.)