What if you would like the file to be global for all users? Before Windows 7 you could place the file in a global location for everyone as described in the Adobe documentation. THis does not appear to work for Windows 7. It will be a real maintenance headache to have to do this everytime a new account is added to a shared machine.
This shortened Adobe manual link describes the Global Flash Player Trust directory: http://bit.ly/fRRV9n
Flash Trust File on Windows 7
I just upgraded my machine to Windows 7 and as always new OS = new paths for config files
Here is the location of the FlashPlayerTrust for Windows 7
Windows 7:
open the following folder:
here create a file with a .cfg extension
now open that file and add a sequence of folder where you want the Flash Player to be able to load local files