I am using XPlane 10 as my simulator and I installed Ground Services. I don't think I misspoken?
Well, what you said you did it's impossible, since GSX won't install under XPlane 10 and cannot possibly run even if you managed to install it manually in some way, the only possible explanation is that you meant something else.
Unless, with "am using XPlane 10 as my simulator and I installed Ground Services", you only wanted to tell that you use XPlane 10 as your simulator, but you installed GSX into FSX, which is also installed in your system, although it's not the main simulator you use.