the saolution for this problem is posted before by McDope.
just download this program:

install it and reboot ur pc.
create the folder "C:\Programe Files" (<- in the case u don't have this folder)
drag the whole Silkroad-Folder in "C:\Programe Files\" while holding the right mouse button, release the button and choose "Junction hier erstellen".
Now it should work... >_>
if u wanna read this in a better english, just read the original-post: