"The calling process must have WINSTA_WRITEATTRIBUTES access to the window station." without this condition, the mouse position cannot be changed with SetMousePos(). The question is: How do I get the WINSTA_WRITEATTRIBUTES access? Or is this access given by default?
GENERIC_WRITE and GENERIC_ALL include the WINSTA_WRITEATTRIBUTES access.
If u didn't set any of these options manually for the current window station u have to create a new window station by using CreateWindowStation() oder set the attributes manually by using SetSecurityInfo().