Your system worked out pretty well. The only thing is, you have made it a lot harder on yourself than it has to be. If each world has a very specific Map ID, Map X and Map Y, you don't need to use all of those variables to check event locations, etc.
Basically, you have it set up on a password system, so you can code it just like a password. No checks needed.
Just write down every Stargate's Map ID, Map X and Map Y on a piece of paper. Now, combine them to make your 7-digit code that the player will input. Now, have the DHD call a Common Event. In the Common Event, set up Conditional Branches for each of the passcodes.
For example:
You have two Stargates.
To reach Stargate 1, you need to input 1234567
To reach Stargate 2, you need to input 4567890
Input Number: [001] 7 digit(s)
@Conditional Branch: Variable [001] = 1234567
<>Transfer Player (use direct transfer by clicking on the map you want and the location on the screen you want to transfer them to)
End Branch
@Conditional Branch: Variable [001] = 4567890
<>Transfer Player (transfer them to Stargate 2)
End Branch
Now just keep going for every gate. If you put each Conditional Branch inside each other (in other words, put the Conditional Branch for Stargate 2 inside of the Conditional Branch of Stargate 1, put Conditional Branch for Stargate 3 inside of Stargate 2, etc), you can use the Else handler to give the "Not Valid" message if the passcode the player entered is not one of the destinations.
Even if you have 20 worlds, you would only have to code 20 Conditional Branches, which really isn't too bad, considering all the time it probably took for you to develop the system you are using right now.
As for your system, it is really pretty innovative. You did a really good job, you just don't need to have all that work.
I still could not get the second link to work, though....