NPC help plz!

I only added the knockback then it dosent work anymore ?!?

Orc01:
Type: zombie
Disguise:
Type: Player
Player: Orc
Skin: GophersVids
Equipment:
- BanditHelmet:4
- stone_axe:0
Display: '&fOrc'
AIGoalSelectors:
- 0 clear
- 1 meleeattack
- 2 randomstroll
Health: 500
Damage: 50
Options:
MovementSpeed: 0.4
PreventOtherDrops: true
KnockbackResistance: 1
Drops:
- exp 1 5
- money 3-6