Stepper making noises but not moving very much (no replies)

Hey guys,

I got this arduino mega/ramps/pololu combo [www.ebay.com] from china last week.
Put everything together (as every single piece was separate) and tested.

The result wasn't very pleasent. I have the same problem with all my motors on that ramps. They make a noise and then (some of them) turn violently when I try to move them using Repetier's manual control interface.
I tested the same ramps with a different pololu (that I have form another ramps on a working printer) and I had the same result.

Here is the video

[www.youtube.com]

Thanks is advance!