Capture picture function disabled ??

[ckkaris]

Hey!
Okay, I'm not a computer genius.
I got BSPlayer to make screencaps, at someone's instruction, and when I hit P or Shift P I get nothing but a green picture with the outlines of the picture, and it's a mirror-like image (complicated to explain)
I have Windows XP, and i"m taking from either AVI or MPG shows that I have downloaded. Anyone know what my problem could be? And how to fix it.

Thanks