[VB6 - API] - using bitblt in same picturebox

[joaquim]

i build 1 code for put 1 image in 1 picturebox, and until here works fine:

ImageWithControls Extender.Container.hwnd, picGraphicsEffects.hDC
        picGraphicsEffects.Picture = picGraphicsEffects.Image
        Call BitBlt(picGraphicsEffects.hDC, 0, 0, PicAnimation(lngActualSubImage).Width, PicAnimation(lngActualSubImage).Height, picGraphicsEffects.hDC, lngOldPosX, lngOldPosY, vbSrcCopy)

then i use the bitblt for copy 1 part of that image to the same picturebox. the result of the function is '1'. but i can't see the part of the image
because the position isn't correct. i know these because i debug it and the position is correct, but the bitblt interpret it by 0. and i don't know why
can anyone explain to me what isn't right?
thanks