Version of BSPlayer? Windows version?
Did you perhaps also install e.g. VobSub (green arrow in system tray)?
You can check to be sure what type of video it is DivX or .e.g. XVid using e.g. GSpot (see the 2nd item of my
Help to Help post (a link to that post is at the bottom of this post))
P.S.: Lots of similar posts!! E.g. click on "Search" at the top of this page and type in "upside" (without the quotation marks) as keyword and then [Enter]