video files corrupt after moving from 1 location to another

This may be a permissions issue. It bit me recently after a Windows reinstall. After you've moved a file, try renaming the file at the new location. If it's the same issue I'm having, you won't be allowed to.

I've got the same username in Windows and on the NAS so drives map automagically, but if I move a file from one location on the share to another location on the share, Windows does something hinky with the permissions and I start getting "You need permission from <NAS hostname>\<my username>...". The ownership and permissions are identical before and after a move according to the NAS, but I can't read the file until I either reset the permissions via the web interface or (bizarrely) give ownership of the file to root. I think it's probably fixable with some config tinkering but it's quite annoying in the meantime.

Anyway, try renaming a new file. It may well be that your files are fine and not corrupted (you could also check the VLC log or debug interface for confirmation), but you just can't read them.