I've just had this issue. Not sure how I've fixed it, but it is now fixed.
Uninstalled it entirely, redownloaded a fresh copy, reinstalled as admin, program to program files and data to my P3D folder.
I've just done a fresh install so had to install quite a few windows related things, net framework etc, not sure if these would have any effect on Global but its the only thing I can think thats changed since I tried to reinstall it again yesterday!