In a campaign I'm working on, I have tried to get the Installation doors to open when the player brings units to a location. The trigger works as follows:

Applies to: Player 1
Conditions: Player 1 brings at least one any unit to Door One Location.
Actions: Disable doodad state for 1 Left Upper Level Door at Door One Location for All Players.

(I might have mis-typed the Set Doodad State syntax, sorry.)

Okay, there's a couple possible problems:

1. You are trying to open multiple doors, that requires an action for each door.
2. You are using the action on the wrong door type(ie, it's actually a Right Upper Level Door)

Check to see if any of that is true.

I'm not doing either. But... Just remembered this. I was afraid of trying to open the wrong type of door, so I used four Set Doodad States, and set each one to disable a different type of door. Might that have been messing things up?

Also, how big does the location have to be? I set it to completely fill the area in the green box that appears when you select the door in the Doodad layer.

And I know my trigger is firing, I checked that by adding 'Display text message: Door should be opening now' to the trigger. It did appear.

Figure out exactly what the door is, and try just doing it for that one, also, try also finding the exact player and using that instead.