FSX Atl-Tab crashes my fsx

i got the update for active sky and wanted to use it, so i fire up fsx, get to the airport with the plane, etc then alt-tab out to desktop, thats fine, fire up active sky, do the refresh thing and then try to go back to fsx and it just locks me out!, i tried alt-tab and clicking on it at the taskbar, etc, still nothing, i have to use task manager to stop it, so i can exit, i cant seem to use anything with fsx that requires me to alt-tab to the desktopany ideas/help? thanksciao!Brian S