Nice to know it worked all right in the end.
It is somewhat strange, that the launcher was able to see the en_UK values of the registry, while the patcher obviously read those too (there would habe been a waring about unsupported languages else) but forgot to store the value in the language session variable.
There is no need to run the patcher manually with admin rights (right-klick->run as admin), because it was set to demand it anyway.
Since it got fixed by the reinstall I guess sth. was wrong, but I cannot tell what exactly. XD
Czevak will be ready when the new version of the patch ?