It seems that scenery AFCAD is full of problems, see here:
http://www.fsdreamteam.com/forum/index.php/topic,10201.0.htmlIt's very difficult to understand what's wrong with a screenshot in the dark but, in any case of vehicles placed too close to the airplane, the most likely cause is the parking radius has been set too low, usually to force some kind of AI to go there, which was a practice in fashion with FS9, not needed on FSX anymore (since it has working airline tags on the parking spots).
Of course, GSX allows you to customize everything, without having to change the scenery AFCAD, I suggest reading the GSX Manual at the pages that explain all the Airport customization options, you can BOTH specify a new radius for the parking, or individually customize the starting positions of every vehicle at every parking.