I still do not understand why I have to reinstall GSX but I will uninstall and reinstall then.
Nobody said you have to uninstall GSX first. If it was required, the message would said that. Just download the latest GSX full installer.
There is a reason why we *require* the GSX updated full installer now: it's not very smart or very efficient to re-include, over and over, the SAME copies of the SAME files like jetways, their textures, docking systems, marhsallers, etc, in each and every installer of every scenery we made. Much better to have all together, in the same place, which is the GSX installer. You'll have to update it now, but won't be required to be re downloaded again for a while.
It's a matter of efficient bandwidth consumption too. We *could* theoretically let you updated everything just with the Live Update but, the Live Update downloads the final uncompressed files as they are, while the installer have them compressed fairly efficiently so, instead of having to force everybody to wait for a 3GB Live Update download, we just ask to download and install 1GB of the new GSX installer, which you can download with your favorite browser, with a download accelerator, at the office, etc...