Hi Jason.
Thanks for your answer,
I tried to change the language into English, but that didn't help. Also, the computer using Windows 8.1 on which the program ran without problems (as I mentioned previously) is set to German. So I don't think that's the problem. Did you look or try the file itself? Does it work on your computer?
One odd aspect when we try to run the program on the Windows 7 computers (where they don't work) is also that DirectRT seems to be trying to use the files. The programs seems to be in action (as indicated in the task manager) and the status bar below indicates it is reading the file, but it never even goes to full-screen mode, and the experiment never starts.