I am having the same problem here. We have lots of MTS files. We are on Windows 7 with Premiere Pro CS6. If you double-click the MTS in Windows Explorer, it plays sound. If you drag it to the Premiere project it does not. I read your post about media browser, so I tried that instead of dragging and unfortunately it still does not work.
If I convert them with HandBrake, they work, but there are lots of files and I would really prefer to use the originals directly. Since the play fine in Windows Explorer isn’t there some way to make Premiere play them?
Thank you very much.