Would this error occur if Couatl had trouble finding my FSX registry entry?
No.
Could you share some insight as to the nature of this error?
As I've said, the error message says it can't write in YOUR OWN %APPDATA% folder, which is not normal at all. The whole point of using the %APPDATA% folder ( which is C:\\Users\\Chris\\AppData\\Roaming\\ in your case ), is that this folder is guaranteed to be ALWAYS writable, on a working Windows installation, by the user account that is running.
It seems your user account has problems, or you have wrong permissions set on your drive. As I've said, it's something that simply shouldn't happen.
Have you done something like reinstalling Windows without reformatting, using the same user name as before the reinstall ?