I compiled the file you sent me and placed it in Addon Scenery\scenery. I compared the compiled file to your project file. All the comms and parking are present in the compiled Bgl file. I then started FSX and ensured that the scenery database updated. I loaded AR51. All your parking spots and start positions are available. I was able to open communications on your ground frequency.
Please zip up and email me the Bgl file you created. I will then check that. However it seems likely that there is another Bgl file containing AR51 on your system and that has priority over yours. Make sure that you did not compile the airport before you added your enhancements and delete it if it is still present. Make sure that you only compile to FSX when it is not running. If you have FSX Airport Scanner then you can check to see if you have another AR51 (perhaps one you downloaded?) that is present and is at a higher scenery priority than Addon Scenery\scenery.