[Vb6] AlphaBlend API function(strange result)

[joaquim]

look these lines in UC:

 'these if is for be changed
    If blnTransparentImage = True Then
        Dim BF As Long
        Const USE_BITMAP_ALPHA = &H1000000 'AC_SRC_ALPHA scaled up to the 4th byte of a long
        BF = 128 * &H10000  'semi transparent ignoring bitmaps alpha channel
        BF = 255 * &H10000 Or USE_BITMAP_ALPHA 'fully opaque using bitmaps alpha channel
        picGraphicsEffects.Picture = UserControl.Image
        AlphaBlend UserControl.hdc, 0, 0, UserControl.ScaleWidth, UserControl.ScaleHeight, picGraphicsEffects.hdc, 0, 0, picGraphicsEffects.ScaleWidth, picGraphicsEffects.ScaleHeight, BF
    End If
    'the next line is need too... when the shadow is desactivated
    UserControl.Picture = UserControl.Image
    PicAnimation(0).Tag = ""
    Call SubTransparent 'these sub is for put 1 color(backcolor) hide
    RaiseEvent ChangeImage(lngActualSubImage)

and theres the result(in image)....
why these strange result?
can anyone help?
thanks