it's hard to imagine for monolinguists, but polylinguists often have different preferences for different software/books.
currently, the installer forces users to install opennx in the same language as the OS.
so anybody who wants to run opennx in a decent technical language will have to buy windows professional (ca. 100USD) to switch OS-language. that's hardly a requirement any open source software should have.
to make matters worse: even when you download the installer from the proper English download page, you'll end up with a setup routine that welcomes you in your OS-language.
as a general remark: it's already annoying to switch webpages to English (how is my country relevant to my language preferences?). opennx's webpage is displayed in the correct language (English) so i was quite shocked to be greeted in Deutsch by the installer.
either offer an english installer from the english page or offer an universal installer whose first question is: Which language would you like to use?