PixelChecksum

[zabouth1]

hi i am haveing some trouble with the PixelChecksum if i try and the the code below i get a "error allocating memory"

Sleep(1500)
$checksum = PixelChecksum(778,778, 150,150)

; Wait for the region to change, the region is checked every 100ms to reduce CPU load
While $checksum = PixelChecksum(778,778, 150,150)
  Sleep(1500)
WEnd

MsgBox(0, "", "Something in the region has changed!")

but if i chance it to

Sleep(1500)
$checksum = PixelChecksum(0,0, 50,50)

; Wait for the region to change, the region is checked every 100ms to reduce CPU load
While $checksum = PixelChecksum(0,0, 50,50)
  Sleep(1500)
WEnd

MsgBox(0, "", "Something in the region has changed!")

I can't work this out how can changing the pixel cause this error?

[BigDod]

Try

Sleep(1500)
$checksum = PixelChecksum(150,150, 778,778)

; Wait for the region to change, the region is checked every 100ms to reduce CPU load
While $checksum = PixelChecksum(150,150, 778,778)
  Sleep(1500)
WEnd

MsgBox(0, "", "Something in the region has changed!")

I have reversed the co-ordinates.