How do I get this door to actually move down?

[ConorMacLennan]

I've got a door tagged to a switch, which is supposed to open when the player has one key of each colour. However, while the switch activates when it is pressed, the walls do not lower (even though a sound plays), and I have no idea why.

Here are some pictures of the area to hopefully identify the problem (textures are placeholder.)

http://imgur.com/a/MtMhC

[Da Werecat]

Looks like the door touches another sector or sectors with the same ceiling height. Doors move to the lowest ceiling they share a linedef with, therefore this door has nowhere to move.

Delete the colored pillar sector(s). These pillars should be made of void.

[edit]

Wait, you want it to go down? That's not really a door. Nevertheless, the problem might be similar, but this time it also depends on the action you're using. More specifically - on the destination of the moving floor.