try this instead
"draconiumOre": {
"template": "uniform",
"block": {"name": "DraconicEvolution:draconiumOre",
"clusterSize": 4,
"numClusters": 16,
"minHeight": 2,
"maxHeight": 128,
"retrogen": "true",
"biomeRestriction": "none",
"biomes": [
"all"
]...