Have you read BSPeter's
"READ THIS FIRST BEFORE POSTING" post (in a particular way items
(2) (3) and
(4))?
Try to see if in the color controls the brightness is too low (right-click on BSplayer -> Video -> Color controls).
Otherwise try to change Video rendering mode (CTRL+P -> Video -> Video rendering).
But probably the problem lays in FFDShow.. Update your version
here. Which filters are used by BSplayer to decode the video? (right-click -> Options -> Filters)