how can i create shape button with script ?

hi
i would like to press button create- spline - recangle button with hwnd way

i modified sample code but error

what problem ?

fn pressButton hwnd: name:"OK" =
(
if hwnd == unsupplied do hwnd = DialogMonitorOPS.GetWindowHandle()
UIAccessor.PressButtonByName hwnd name
)

hwnd = windows.getchildhwnd #max "Create Shape"

DialogMonitorOPS.unRegisterNotification id:#rectangle
DialogMonitorOPS.RegisterNotification pressButton id:#rectangle
DialogMonitorOPS.Enabled = on
UIAccessor.PressButton hwnd[1]
DialogMonitorOPS.unRegisterNotification id:#rectangle
DialogMonitorOPS.Enabled = off