I have nearly completed a Rostock build based upon RichRap's rostock printer. The printer is using an Arduino 2560, Ramps 1.4, NEMA 17 stepper motors, and Repetier Host. The printer appears to move correctly in they X and Y directions. However, when I manually hit 1mm movement in the Z direction on Repetier Host, the printer moves about 120cm. I have all 3 jumpers connected under the stepper driver for the z axis. I cannot figure out how to reduce the travel in the z direction. Any suggestions? Thanks!

Sounds like you don't have the right configuration for a delta installed on the Ramps.