Tile Map Collision Problem

I get the feeling that there's something really obvious that I'm missing here, but I can't figure out what.

I was trying to get my player object (this is a test game, so I'm using all images that came w/ T2D) to collide with the tile map I made, but to no avail. So I turned on the debug for the tile layer (not map) and the object, but I don't see any collision boxes around the tiles. I copied this code from a source and changed it so that the tiles would actually show up, so I don't see why it wouldn't work. Note that this is the code after a variety of rewrites; I didn't originally use brickMap and Layer -- they came from the copying part that I was too lazy to rewrite.

$brickMap = new fxTileMap2D() { scenegraph = t2dSceneGraph; };
	$brickMap.loadTileMap("~/client/maps/leveltest.map");
	$brickLayer = $brickMap.getTileLayer(0);
	$brickLayer.setPosition("0 -125");

	// setup the layer collisions
	$brickLayer.setGroup(1);
	$brickLayer.setLayer(1);
	$brickLayer.setSize( "100 80" );
	$brickLayer.setPosition( "0 5" );
	$brickLayer.setCollisionActive(false, true);
	$brickLayer.setCollisionMaterial(immovableMaterial);
	$brickLayer.setCollisionMasks(BIT(2), BIT(2));
	$brickLayer.setCollisionCallback(true);
	$brickLayer.setCollisionPhysics(true, false);
	$brickLayer.setDebugOn(BIT(5));

The bounding box shows up fine for my player, so I don't see why this isn't working. Any ideas? Again, it's probably really obvious, but after a few hours I gave up and decided to post here.

-darkhitman