Lodestar gone noisy

Tonight, I could not get autoguiding to work. I connected PHD and started to take images and saw many stars. But every time I tried to calibrate, the mount would not move. First, I was afraid that the new autoguide cable would be broken as well. But then I moved the scope manually and realized that almost all of the stars did not move. And that the only stars that moved were VERY faint. I took a series of dark images. Combined they lead to this:

I tried several times - always with the same result. Then I thought that my scope might be "leaking somewhere" and took darks in a dark room:

Sh###!!!

I have no idea what to do here.