[CentOS] Problem with gnome with file type recognition.

I have a problem with some file recognition with gnome (CentOS 5.2).

I have some DVD with AVI files I burn some time ago (and the files were
checked and the DVD are fine), and curiously only the 3 or 4 first files
were recognized as AVI files, but the rest not!.

I another times, appears to recognize all files, but from some days to now
I have this problem (specially with AVI files).

The recognized files are played fine with xine, mplayer or vlc, but the
rest not, the players don't know how to play them (very courious this
issue).

Do anyone know how to solve this? Could be any system component that
wasn't working fine? (as any daemon, or the DVD reader) Anyone know how to
test my DVD writer/reader or any system/gnome components that could be
missconfigured or not working?

Regards