Aircraft problem

Aeturnalis

Maybe someone can help...

I have added an aircraft that i downloaded from here to the game for the allies. Everything works correctly except one thing:

the build limit doesn't exist.

I can build more than I have docks for. Since I made it for the allies, I copied/pasted the code from the Harrier, and changed these things:

weapon, cost, strength, and prerequisite.

Once all 4 docks on the airforce command hq are filled, I can still build it, but the build countdown stops at about halfway and doesn't go any further. If I click on it again, instead of adding one to the queue, it starts over then stops about half way.

Any suggestions on how to add more aircraft types to the game and maintain the build limit to the number of free docks?