Problem z 'loop blocks within x to x'

A więc mam problem z tym skryptem:

loop blocks within -23, 137, -157 to -27, 134, -166:
		set block at loop-block to iron ore
		chance of 10%:
			set block at loop-block to iron block

Pokazuje się błąd: Invalid brackets/variables/text in '-27, 134,'