The problem is not caused by KLAX, GSX or Couatl but, instead, is likely caused by your FSX.CFG being corrupted or reset, possibly by another addon, so now it's missing the line added by our installers to let it find the scenery objects.
If you or another utility reset or recreate the FSX.CFG, you must reinstall ALL (not just FSDT's) products that needs their path to find objects added as simobjectpaths = xxxx lines in the FSX.CFG
So, normally, a reinstall of any FSDT product should fix this, because our installers will of course add the required lines to the FSX.CFG file automatically but, you should try to identify why you FSX.CFG was reset, otherwise the problem will happen again.