Christoph,
I believe that you were shipped a V2 machine rather than a V1, correct? (The V2 is black, the V1 is silver).
If so, the software setup instructions for the V2 are much more straight forward and does not require the use of putty. The tutorial for the software setup as well as other useful tutorials for the V2 can be found
here.
Hope this helps, let us know if you have any other issues getting going.
Best,
Michelle