Can't assign new build to worker

[Mrblbshrtz]

Here is the situation: I am attempting to make a tiberium mod for Civ 5. I have succeeded in making tiberium a tile feature like fallout (it in fact looks identical to fallout), and have tested this in game. I then tried to add a worker "build" - like scrub fallout. This would scrub the tiberium and provide alot of production to the nearby city. Once I opened this up in game, however, it's not an available option for the workers on the tile. Here is my code:
CIV5Features- where Tiberium is defined:

<?xml version="1.0" encoding="utf-8"?>
<!-- Created by ModBuddy on 29/7/2014 8:54:18 PM -->
<GameData>
	<Features>
		<Row>
			<Type>FEATURE_TIBERIUM</Type>
			<Description>TXT_KEY_FEATURE_TIBERIUM</Description>
			<Civilopedia>TXT_KEY_FEATURE_TIBERIUM_PEDIA</Civilopedia>
			<ArtDefineTag>ART_DEF_FEATURE_FALLOUT</ArtDefineTag>
			<Movement>2</Movement>
			<Defense>-15</Defense>
			<NoImprovement>true</NoImprovement>
			<PortraitIndex>17</PortraitIndex>
			<IconAtlas>TERRAIN_ATLAS</IconAtlas>
		</Row>
	</Features>
	<Feature_YieldChanges>
		<Row>
			<FeatureType>FEATURE_TIBERIUM</FeatureType>
			<YieldType>YIELD_FOOD</YieldType>
			<Yield>-3</Yield>
		</Row>
		<Row>
			<FeatureType>FEATURE_TIBERIUM</FeatureType>
			<YieldType>YIELD_PRODUCTION</YieldType>
			<Yield>10</Yield>
		</Row>
		<Row>
			<FeatureType>FEATURE_TIBERIUM</FeatureType>
			<YieldType>YIELD_GOLD</YieldType>
			<Yield>-3</Yield>
		</Row>
	</Feature_YieldChanges>
</GameData>

CIV5Builds - where scrub tiberium is defined:

<?xml version="1.0" encoding="utf-8"?>
<!-- Created by ModBuddy on 29/7/2014 11:02:39 PM -->
<GameData>
	<Builds>
		<Row>
			<Type>BUILD_SCRUB_TIBERIUM</Type>
			<Description>TXT_KEY_BUILD_SCRUB_TIBERIUM</Description>
			<Help>TXT_KEY_BUILD_SCRUB_TIBERIUM_HELP</Help>
			<Recommendation>TXT_KEY_BUILD_SCRUB_TIBERIUM_HELP</Recommendation>
			<EntityEvent>ENTITY_EVENT_IRRIGATE</EntityEvent>
			<OrderPriority>99</OrderPriority>
			<IconIndex>59</IconIndex>
			<IconAtlas>UNIT_ACTION_ATLAS</IconAtlas>
		</Row>
	</Builds>
	<BuildFeatures>
		<Row>
			<BuildType>BUILD_SCRUB_TIBERIUM</BuildType>
			<FeatureType>FEATURE_TIBERIUM</FeatureType>
			<Production>20</Production>
			<Time>300</Time>
		</Row>
	</BuildFeatures>
</GameData>

CIV5Units- where I specify that workers are able to use this Build

<?xml version="1.0" encoding="utf-8"?>
<!-- Created by ModBuddy on 29/7/2014 11:11:28 PM -->
<GameData>
	<Unit_Builds>
		<Row>
			<UnitType>UNIT_WORKER</UnitType>
			<BuildType>BUILD_SCRUB_TIBERIUM</BuildType>
		</Row>
	</Unit_Builds>
</GameData>

Game Text

<?xml version="1.0" encoding="utf-8"?>
<!-- Created by ModBuddy on 29/7/2014 9:16:38 PM -->
<GameData>
	<Language_en_US>
		<Row Tag ="TXT_KEY_FEATURE_TIBERIUM">
			<Text>Tiberium</Text>
		</Row>
		<Row Tag ="TXT_KEY_FEATURE_TIBERIUM_PEDIA">
			<Text>Insert Tiberium description here</Text>
		</Row>
		<Row Tag="TXT_KEY_BUILD_SCRUB_TIBERIUM">
			<Text>Harvest Tiberium</Text>
		</Row>
		<Row Tag="TXT_KEY_BUILD_SCRUB_TIBERIUM_HELP">
			<Text>Harvests the Tiberium present in this Tile.</Text>
		</Row>
	</Language_en_US>
  
</GameData>

I have an action set, such that when the mod activates, it updates the database with all 4 of these files.

I can't see why this isn't working. Could anyone give it a look over?