have update in a row, 1st addon manager, 2nd latest GSX installer, 3rd latest vehicle installer(dont know if that was right to do but anyway).
Never was no need to install the Stand-Alone Addon Manager or the vehicle updater because, as I've said, the full GSX installer is always updated with *EVERYTHING* so, if you just downloaded it now, there was no need to do anything else.
However, it won't do any harm if you did it.
Tested at 2 airports that I was sure there is not AFCAD error everything went OK, tested at an airport that I have found some errors with ADE, GSX crashed and requested to update addon manager.
Then this is ANOTHER, totally unrelated, crash, that doesn't have anything to do with the all the previous ones. This was surely an error (NOT a crash), that didn't just said to update the Addon Manager. It ALSO said to check your Couatl.ERR for details about the error.
Since you know the AFCAD has errors with ADE, it's just normal it would cause an error in GSX, but if you post your Couatl.ERR file, we might understand what was really the cause for it.