mousemove in window

Alright im trying to get my mouse to click in a certain Window and it never seems to work,

on the desktop i can get it to go where i want but its not working in my other window.

i google searched and found this but cant get it to work for some reason.

Opt ("MouseCoordMode", 1)
 
; And this one
 
AutoItSetOption ("MouseCoordMode", 1)

now i was reading that :

0 = relative coords to the active window

1 = absolute screen coordinates (default)

2 = relative coords to the client area of the active window.

i tried using all those and the 2 code options i posted above. and none seem to work in a specific window.

maybe somebody can toss me some info on why that is.

im using the autoit window info tool. to get the mouse loc x,y