Problems with Capture Frame -> "What you see"

[Id]

Yeah that's right
I got a PixelView GeForce 2 MX400 64 MB on WinXP (if that has anything to do with) and the program runs fine, but...
When I try to capture a frame (doesn't matter if it's a DivX AVI or MPEG), if I use the option "Capture frame -> original size" it works fine and captures the original size...
Now when I use "Capture frame -> What you see", instead of capturing the video's current size (Fullscreen for example, I even tried dragging the video's window), it captures the original size instead.
The only time it worked and that I could get a fullscreen frame captured was when I opened a video and BSplayer reported a sort of Overlay error, but the video would run just fine and so did the "Capture frame -> What you see", but it only happened once.
How can I get that option to work correctly?

Thanks for the help