Joel, I had the same problem as you. After reading design454's solution, I decided to open up the scanner and see what I could see. There are just 4 tiny screws to deal with, so separating the two halves is quite simple.

There's a system of 4 or 5 white plastic gears that revolve the roller. Within 10 seconds of playing with these, I noticed that one of the tiny plastic gear teeth had broken off and was jamming the gears. After I removed the broken tooth, the gears turned smoothly. Screwed the thing back together, and it worked like new! And all it cost me as a $2 precision screwdriver set.

I have 6 of these and there is a white piece of plastic that holds the roller and gears together on the left hand side. I am willing to bet that this piece is cracked allowing just enough play that the gears are binding. I have tried super glue but due to the oil on the parts, I am unable to fix without a complete disassembly. I will post later if I am successful. You might want to look up the "Ambir TravelScan Pro 600" It looks identical and you might find more info with FixYa links there. Good luck.

Thanks! Opened the scanner and pushed the gears around with my finger and screwed it back together. I was skeptical but it worked perfectly. Thank you so much!

I'm having the same issue, but I can't get any of my precision screwdrivers to fit into the whole or to fit into the screws. Can anyone point me to the correct size/type screwdriver?
Thanks,Daniel