Well, I haven't been on the computer for awhile due to an operation on my eyes. Today, I started FSX and noted a message regarding downloading an update to GSX and I shut down FSX and my AVG, downloaded the Stand Alone Addon Manager and installed it. As soon as I did so, a pop-up arrived that not all of the items could be installed and to try again later, but it continued to install whatever it was installing. When the installation completed, I started FSX and receive the error message of this topic. I am running two NVIDIA GeForce 9800, GTX+, 512MB, 256 bit, GDDR3, in SLI, and have no clue as to the reply suggestions contained above. I had no problems with the prior GSX installation.