I think the installation is incomplete - did you try deleting and reinstalling the package? If this happens again you could try a fresh download and temporarily disable your anti virus for the installation.
I've just purchased Aerosoft EGLL, downloaded and installed the files into my X-Plane directory, however when I then load into the sim there are no buildings or markings within the airport, it's just a large plain of concrete. I get a bunch of errors about not being able to find any object files. I will upload the log file and scenery.ini file as an attachment to this post. I've also backed up and removed the Aerosoft EGLL folder that came shipped with X-Plane, but that didn't fix it.
Any support would be amazing!
Thanks in advance,