Hopefully I can fix the subtitle problem before saturday, since I would like to watch the movie then. Mega upload is working at this very moment, but for how long...
TotalMediaTheatre 5 is one of the few players which is able to play the video including subtitles when I open the BDMV folder using the program, but in that case the audio isn't working. The audio does work if I open the video file itself, but in that case the subtitles aren't selectable. Strange strange strange.
Till now VLC is the best solution: audio is playing and subtitles are selectable, but the subtitles are not presented the right way; they just appear and disappear in just a few milliseconds.
-----------------------EDIT------------------
Media Player Classic - Home Cinema x64 is able to play the video including audio AND subtitles (presentation graphics stream 1200,bd,00) the correct way.
I tested Total Media Theatre 5, Cyberlink PowerDVD 11, Corel WinDVD 2010, Media Player Classic and VLC. Only Media Player Classic was able to play the BDMV folder video without any problems. Why? No one knows by now.