I have a weird problem since I installed v1.8: suddenly the pushback happens as usual, but the staff and vehicles doing it are invisible.
Doesn't happen here, and can't be possibly related to the update, since nothing at all has changed in the pushback.
That's not of course anything related to activation of the Addon Manager or anything like that. Without activation, GSX would work in full at the Trial or FSDT airports only, and if there was a problem with the software not running correctly (like antivirus, or similar) nothing would work.
It's not a GSX.CFG issue either because, the only thing a GSX.CFG for an airplane controls in the pushback, is the nose distance to set the truck attach point.
Invisible objects are usually caused by video settings, problems with tweaks, video memory corrupted, too much vram used by other add-ons, etc. Fact that you noticed after the update was just a coincidence.
Try to remove your FSX.CFG located under %APPDATA%\Microsoft\FSX so FSX will rebuild it with default settings. Apply only the HIGHMEMFIX tweak.
