Black image on screengrab

[BustaFunk]

sorry if this had been asked and answered million times.

I have trying so many ways to do screengrab, printscreen, alt+printscree, using the 'P' on WinDVD, capturing using VCD Cutter, and using HyperSnap DX. But the results are just Black screen. Yes Black with no image at all.

Anyne can help me with this? (i'm capturing an MPG file)

[setarip]

You can load the .MPEG file into TMPGEnc and select whichever frames you'd like to save...