Do you get an actual jam or just an error?
If it's an actual jam, is it jamming left or right side - what's the actual description of the jamming that's happening?
If it's just an error, may be a faulty paper sensor (or just dirty). If it's actually jamming, look for an obstruction or something on/obstructing one of the rollers. Watch the paper as you feed it through and see what happens.