I don't have the software, so it is pretty much impossible for me to know the cause. So I'mm gonna gues, and kick in some open doors first:
I assume you have tried the uninstall - full reinstall option already with no result? It appears the original scenery is peeking through the addon scenery, so the priority of the addon scenery is maybe too low w.r.t. the Aerosoft scenery. Check the installed addon scenery list if the Aerosoft one is the top one, just to be sure.
Did you check the Aerosoft support forum? If you have the problem, there are probably others out there that have the same problem...