When Security Blockade enters the battlefield, create a 2/2 white Knight creature token with vigilance.
Enchanted land has ": Prevent the next 1 damage that would be dealt to you this turn."
10/1/2012 You must target a land to cast Security Blockade. If that land is an illegal target when Security Blockade tries to resolve, it won’t resolve and won’t enter the battlefield. You won’t get the Knight token.