Have a look at the last page of the "installation and wizards" thread, especially at the post by MegaMuse, who is also from Germany and explains how to copy and edit the wizard files, to make them work with non-English Windows:
http://forum.thegamecreators.com/?m=forum_view&t=118371&b=22&p=2
However, if VS Express itself gives error messages, that is a bigger problem and I don't know if anyone except MS support can help you with it... Anyway, do you have the latest Windows updates installed? Have you installed also the DirectX SDK? Have you started VS Express at least once before installing Dark GDK? Does VS Express at least start and able to compile a simple program without Dark GDK? If it doesn't even start, all I could suggest is reinstall it...