how can i fix this "Unknown file format XDIV" HELP
 

When I wanna to watch a movie I get a message "Unknown file format XVID", please how i can fix this.

Have you installed the xvid codec? You can find here:

http://www.roeder.goe.net/~koepi/xvid.shtml

I've installed the codec you suggest as well as several others. Bsplayer allows me to play SOME Xvid films, but for others I get the "Unknown file format (XVID)" message.

XVid is still under heavy development with frequent changes. Some of these modifications (for now only affecting "dev" branch (unstable) builds) sometimes result in non-MPEG4 standard videos if you encoded with that codec version. If later on in development these issues have been corrected, your non-MPEG4 compliant video remains unplayable.
No fix that I'm aware of.

Where did you get your file ? Are you sure it isn't corrupted or incomplete ?

When BSPlayer says "Unknown file format ( ???? )" whereas you already installed the codec ????, it always a problem with the file, not with the codec or BSPlayer.

To be sure, try to play it with "the playa", if the playa can, the file is incomplete/corrupted, if it can't, well, I made a wrong statement.

There are two things you can try in case you AVI/XVid is corrupted or truncated.
1) Run VirtualDub, tick open under file tab, check Pop up extended open options box before opening AVI. Then another dialog appears.
Enable Re-Derive keyframe flags.
Click open. Under video tab enable Direct stream copy.
Hit F7 to save AVI again (different name).
Voil?•.

2) There's another tool to repair corrupted AVI files (mostly reindexing):
Link is this one: http://divfix.maxeline.com/.

I get something similar, attempting to open .MPG and .MPEG files:
Unknown file format[]

But if i open the file using, mplayer.exe, it plays fine...

Yesterday I found out that I got this message with some files when using overlay 2. using overlay 1 was fine.

how weird :o