I've been using GSX for the past couple weeks and the only way couatl would work for me is if I ran FSX in Administrator
That's not normal, Couatl run just fine when FSX is run normally.
The problem is likely your User account is not an Adminstrator and this is NOT the same thing as running "As Administrator" so, if you change your user account to be of the Administrator type, you will be able to run Couatl normally, without having to run FSX "As Administrator", which should fix the problem you have with the other product.
I repeat: having an user account with Admin rights, is NOT the same as running FSX As Administrator.