I don't think you downloaded a file from this site with 20 airports of ours in one file. We've not released anything like that. So, not sure how to help you on that.
Only thing you can do is delete any RTMM files you have that aren't working, and install our scenery as we recommend it to be installed. One area at a time. We don't put out any group packages and don't recommend any of our scenery to be installed in a group of files. Precisely for the reason's you are expressing in your problems, you can't be sure what's gone wrong and we can't really help you because of that.
Sorry,
Brad