Works OK for me. Screen is captured. Below are the details:
------------------------
BLUESTACKS
------------------------
BlueStacks is open and not minimized
Resolution: 860, 720
------------------------
AUTOIT
------------------------
Version: 3.3.12.0
Native x32
Au3 Script
------------------------
SPECS
------------------------
CPU: X64
OS: X64; WIN_7
------------------------
DESKTOP
------------------------
Aero Enabled
Depth: 32
Resolution: 1024, 1600
Refresh rate: 60
------------------------
FUNCTION CALL
------------------------
_WinAPI_GetDC: 0x1C01120F
_WinAPI_CreateCompatibleDC: 0x1D011160
_WinAPI_CreateCompatibleBitmap: 0x4E05119D
------------------------
BLUESTACKS
------------------------
BlueStacks is open and not minimized
Resolution: 860, 720
------------------------
AUTOIT
------------------------
Version: 3.3.12.0
Native x32
Au3 Script
------------------------
SPECS
------------------------
CPU: X64
OS: X64; WIN_7
------------------------
DESKTOP
------------------------
Aero Enabled
Depth: 32
Resolution: 1024, 1600
Refresh rate: 60
------------------------
FUNCTION CALL
------------------------
_WinAPI_GetDC: 0x1C01120F
_WinAPI_CreateCompatibleDC: 0x1D011160
_WinAPI_CreateCompatibleBitmap: 0x4E05119D