MaskBlt - Error 6

I've been trying to use the maskblt api and nothing happens, so i called the getlasterror api and it told me that there is an invalid handle (ERROR_INVALID_HANDLE = 6&), i think its the hbmMask parameter, so can someone explain exactly whats supposed to be passed to that parameter, can't it just be the hDC of a picture box?

try using the hWnd of the picturebox instead.

Or perhaps Picture1.Picture.Handle