No sound on ATV Flash

Hi

I have several weeks without using my ATV FLASH and the last time I use it it was working without any problem, now I have a problem when I play a movie uploaded with Cyberduck no sound come on, but if I play a song or a video music uploaded with iTunes the sound works well.

Please help

Thanks

What format are the movies?

All are in RMVB

For RMVB files you will want to ensure the ‘Mplayer Codecs’ have been installed through the nitoTV --> Settings --> Install Software menu.