videos not playing on smartphone

I am not able to play the videos on my smartphone. Even after trying to change the user agent on the browser settongs, I get the error: File has incorrect data. I just bought this course today and really like the crossword game but am frustrated with the videos not playing and the extreme elementary course. Is there an intermediate and advanced course? Any suggestions about the videos not playing?

I should add that the dictionary videos play fine. It's the course videos that bring up the mentioned error or do nothing at all with no error pop-up, depending on user agent. I am using an Android, Samsung Infuse.