Nothing in your error log shows anything related to the airport cache. Instead, it's seems there's a problem with your FSX.CFG, which is missing the lines added by our installer to let it find FSX objects.
Do you have some external addon that has reset the FSX.CFG file ? Of you reset/edit it yourself ? In that case, reinstalling GSX after the FSX.CFG is being reset to default SHOULD fix the problem but, if your FSX.CFG is *corrupted* instead, our installer won't touch it, hence the error.
So, first try to reinstall GSX. If that doesn't work, post your FSX.CFG in ZIP form, as an attachement, and I'll look at it, to see if there's a problem with it.
The file is located under %APPDATA%\Microsoft\FSX, on a stand-alone (no old FSX) installation.