When application is minimized, _Screen.WindowState = 1

>I use the following code in all my programs:
>"ON SHUTDOWN DO EXITAPP"
>In the EXITAPP.PRG, I open a user database and save settings when the program closes, such as _screen.top, _screen.left and other data like that so I can use it when the program starts up again. All works fine, but I have one user that informed me that if he minimizes my VFP program and then right-clicks on it in the taskbar and clicks CLOSE, the program maximizes and then generates the following error message:
>"Numeric overflow. Data was lost." If I click on [Ignore], it tells me the variables that I am saving in my EXITAPP are not found. Is there a solution to this problem or a work around, or a way to test if the program is trying to be shut down this way that I could tell my program to bypass the saving of these variables that are not available at this point?