1) Download bsplay100.803.zip file from
www.bsplayer.org website, unless you already have that .zip file
2) extract the .zip contents to wherever you installed K-Lite codec pack
that came with bsplayer (default location c:\program files\k-lite codec pack\bsplayer) overwrite files there if asked.
3) re-assign .avi, .bsi file extensions to bsplay.exe or alternatively make a copy of bsplay.exe over bplay.exe so that bplay.exe now refers to newer version of BSPlayer.
Should work.