Hi adrianwolff
I'm not from Laminar Research, just a fellow simmer in the UK but what scenery packs did you purchase and are you running MAC or Windows?
I only ask, as I had a similar problem with some plugins once and later found out that I had inadvertently installed some MAC files instead of the ones for Windows. Files for MAC operating systems have a slightly different file name to the ones in Windows!
Are you able to send a screen print of your Custom Scenery folder/file layout?
Regards