stopping pda using X button - labview

I tried this approach but ran into a problem.  I turned the main VI into a renamed subVI and created a Main VI that is identical to the PDALauncher vi  in the example (except I substituted my subVI for the one called by the example).  Now, whenever I try to build the app, I get an pop-up small box from LabView that says simply "Bad VI" and simultaneously shows the Error Box that has a big red X error indicating there is a fatal error in my former main VI (which is now a renamed sub VI).  However, the "Bad VI" error message box is a modal pop-up box that I must click OK until anything will continue.  After I click on OK, the sub-VI error indication immediately goes away in the standard Error Box and the Error Box changes to indicate there are no VIs with errors, but the build does not proceed.  So I get no indication at all from LabView about what the problem is and I cannot proceed with a Build.
Any help will be appreciated.
Jerry
 

Brian, et. al.
I took your advice and that cured the problem. 
Thanks to all for your help.
Jerry