It seems for all airports I go to, GSX uses the FSX Stock AFCAD instead of using the supplied one from the publisher. This leads to inaccessible ground services because the majority of the parking spaces/taxiways are misaligned.
GSX recognizes any AFCAD, provided it doesn't contain errors and is self-contained. Self-contained means the AFCAD is complete, and contains all parkings and taxiways layout. Some AFCAD authors don't include everything, but only modifications of the stock AFCAD so, FSX will get the complete information both from the stock AFCAD and by the scenery AFCAD together. GSX doesn't support this configuration, but it's not very common, especially with commercial sceneries, which are usually all self-contained.
GSX regenerates airport cache, but seems to stop at 22%.
That progress indicator doesn't mean much, it will go from 0 to 100% only if the whole Scenery Library has to be updated. But if you just installed a single scenery, it will be very quick and will not display the 100%, because the process will be finished before the text gets updated so, it's not an indication of a problem.
I've tried to reinstall, that didn't work, so I came here. Any suggestions would be appreciated!
The first thing to try would be forcing FSX to regenerate the whole cache, by removing the following folder:
C:\ProgramData\Microsoft\FSX\SceneryIndexes
Then wait for FSX to regenerate its cache, followed by GSX that will regenerate its own too. Eventually, you might also try to Restart Couatl from the Couatl menu, after the whole regeneration is done.