Thanks for the feedback wgstarks, both capfuturo any yourself reported this problem.
I believe that it is because you are running with "Store tunes in custom path" enabled. The movie themes need to be in the local directory to the movie (as it is not something that TvTunes can fetch for itself).
I believe if you disable "Store tunes in custom path" then you will hear the Movie Theme - however you will obviously lose your TvThemes (as they are stored in the custom location).
I have commited a fix for this, so you should be able to patch this OK.
Please let me know if this solves it for you
Edit: Just wanted to clarify the version of this one, this change refers to r10, direct link: