Trouble with Full Screen Movies

I have the movies working correctly on Blitz3D in windowed mode, but I can see just a black screen in Full Screen Mode.
Anyone knows why?

Here's my simple PlayMovie function:

Function PlayMovie(movieName$)

ClsColor 0,0,0
SetBuffer(BackBuffer())

movie = OpenMovie(movieName$)
If movie = 0 Then RuntimeError movieName$ + " not found!"
If Not(MoviePlaying(movie)) Then RuntimeError "Error - Movie not playing!"

While (MoviePlaying(movie)) > 0 And (Not KeyHit(1))
Cls()
DrawMovie(movie, 0, 0, 640, 480)
Flip()
Wend

CloseMovie(movie)

End Function

This code works fine for me. I noticed that I had to set the mode to 32bit in order for the colors to come out correctly though.

Graphics 640, 480, 32
ClsColor 0,0,0
SetBuffer(BackBuffer())
moviename$ = "G:\My Movies\my movie.avi"
movie = OpenMovie(movieName$)
If movie = 0 Then RuntimeError movieName$ + " not found!"
If Not(MoviePlaying(movie)) Then RuntimeError "Error - Movie not playing!"

While (MoviePlaying(movie)) > 0 And (Not KeyHit(1))

DrawMovie(movie)
Flip()
Wend

CloseMovie(movie)

since DrawMovie will limit the framerate to the movie rate anyway, you may try to use flip 0.