EXEs and LabVIEW or other EXEs have their own seperate memory space, so the Global you've put in your application has its own copy of the Global VI you created which it is using and is no longer pointed ot the Global VI your other applications are using.
You can use the ActiveX or TCPIP VI servers to pass data back and forth, or use numerous othe protocols such as data socket, your own TCP/IP or UDP service, etc.