I downloaded the file and began installing. All goes well until the process stops with the message shown in the attachment. Why the "No Internet Connection"? I am on the internet during the entire process. Have been trying to install since yesterday. No anti-virus running, install as Administrator.
The problem might be caused either by a firewall/antivirus that is blocking online access to the installer, or by one of the two installation servers being down. Since they are selected at random at start, you might just try it again, and eventually you'll hit the server that is up.
However, since you said you just downloaded the installer, the online files are not really needed, they are the same as the one included in the installer. Which means, when prompted to press "Next to use local files", just press Next, and the installation will be the same.
AttributeError: 'AircraftData' object has no attribute 'exits'
This seems to indicate you are trying to use GSX with an unsupported airplane, that wasn't made for FSX, so it's missing the [Exits] section in the correct FSX format.
Try to use a default airplane first, to be sure everything's working. Then, if you want to use an unsupported airplane, you must create a GSX config for it, using the integrated airplane configuration utility.