As I see no one is answering, I'll offer a possible solution. If your file name is too long, Windows (or whatever OS you are running) may have a problem with it. Applications will not be able to read them correctly if the OS can't handle it. Try changing the file name to something short. Also, if the file is huge, like a 2.2 GB avi on a Fat32 partition, then it won't play. There is also a limit on NTFS partitions, but it's something like over 4 TBs, so if you are using NTFS (like NT, Win 2k, XP), the file size in bytes shouldn't matter.

Hope this helps. :-)