Since firmware update (.m4v/.mp4) movies don't play

Hi all,

I have a WDTV live smp and since the firmware update some videos are not playing. When I click on the video to play in my media library, the little arrow thing goes around for a second, and then it brings me right back to the screen I was at to select the video. It seems like this is only happening with .mp4/.m4v and my .mkv files work okay. I don’t understand why this is happening because all worked fine before this last update. Is anyone else experiencing this?