Whenever I try to use a building planner to build something I get kicked with this error.

Creating item with less than 1 amount! (Wood)
NullReferenceException: Object reference not set to an instance of an object
  at (wrapper dynamic-method) Planner.Planner.PayForPlacement_Patch0(Planner,BasePlayer,Construction)
  at (wrapper dynamic-method) Planner.Planner.DoBuild_Patch0(Planner,Construction/Target,Construction)
  at (wrapper dynamic-method) Planner.Planner.DoBuild_Patch0(Planner,ProtoBuf.CreateBuilding)
  at Planner.DoPlace (BaseEntity+RPCMessage msg) [0x0001a] in <d104bd9431fb46e3a23ef8d5f90cd4ac>:0 
  at Planner.OnRpcMessage (BasePlayer player, System.UInt32 rpc, Network.Message msg) [0x000d5] in <d104bd9431fb46e3a23ef8d5f90cd4ac>:0 
UnityEngine.DebugLogHandler:Internal_LogException(Exception, Object)
UnityEngine.DebugLogHandler:LogException(Exception, Object)
UnityEngine.Logger:LogException(Exception, Object)
UnityEngine.Debug:LogException(Exception)
Planner:OnRpcMessage(BasePlayer, UInt32, Message)
BaseEntity:SV_RPCMessage(UInt32, Message)
ServerMgr:OnRPCMessage(Message)
ServerMgr:OnNetworkMessage(Message)
Facepunch.Network.Raknet.Server:ProcessRead(NetRead)
Network.BaseNetwork:Cycle()
ServerMgr:Update()​

Please share your config, which permissions you are using, and which version of the plugin you are using.

This is my current config and I use craft_most_items and unlimited_ammo permissions. I am using adminmenu for handling the permissions. I'm using the current version 0.5.1. once I disabled this plugin the error went away. Edit: I hope it's not because of the wood setting being zero lol

{
  "Rulesets": [
    {
      "Name": "build",
      "All deployables are free": false,
      "Free deployables": [],
      "Items": {
        "metal.fragments": 10000,
        "metal.refined": 10000,
        "stones": 10000,
        "wood": 0
      }
    },
    {
      "Name": "unlimited_ammo",
      "All deployables are free": false,
      "Free deployables": [],
      "Items": {
        "ammo.grenadelauncher.buckshot": 100,
        "ammo.grenadelauncher.he": 0,
        "ammo.grenadelauncher.smoke": 0,
        "ammo.handmade.shell": 100,
        "ammo.nailgun.nails": 100,
        "ammo.pistol": 100,
        "ammo.pistol.fire": 100,
        "ammo.pistol.hv": 100,
        "ammo.rifle": 100,
        "ammo.rifle.explosive": 100,
        "ammo.rifle.hv": 100,
        "ammo.rifle.incendiary": 100,
        "ammo.rocket.basic": 0,
        "ammo.rocket.fire": 0,
        "ammo.rocket.hv": 0,
        "ammo.rocket.smoke": 0,
        "ammo.shotgun": 100,
        "ammo.shotgun.fire": 100,
        "ammo.shotgun.slug": 100,
        "arrow.bone": 100,
        "arrow.fire": 100,
        "arrow.hv": 100,
        "arrow.wooden": 100,
        "snowball": 100,
      }
    },
    {
      "Name": "craft_most_items",
      "All deployables are free": false,
      "Free deployables": [],
      "Items": {
        "bone.fragments": 10000,
        "can.tuna.empty": 10000,
        "cloth": 10000,
        "electric.rf.broadcaster": 10000,
        "electric.rf.receiver": 10000,
        "fat.animal": 10000,
        "gears": 10000,
        "ladder.wooden.wall": 10000,
        "leather": 10000,
        "lowgradefuel": 10000,
        "metal.fragments": 10000,
        "metal.refined": 10000,
        "metalblade": 10000,
        "metalpipe": 10000,
        "metalspring": 10000,
        "propanetank": 10000,
        "pumpkin": 10000,
        "riflebody": 10000,
        "roadsigns": 10000,
        "rope": 10000,
        "semibody": 10000,
        "sewingkit": 10000,
        "sheetmetal": 10000,
        "skull.human": 10000,
        "skull.wolf": 10000,
        "smgbody": 10000,
        "spear.wooden": 10000,
        "stash.small": 10000,
        "stones": 10000,
        "syringe.medical": 10000,
        "targeting.computer": 0,
        "tarp": 10000,
        "wood": 0
		
      }
    },
    {
      "Name": "craft_all_items",
      "All deployables are free": false,
      "Free deployables": [],
      "Items": {
        "ammo.grenadelauncher.buckshot": 0,
        "ammo.grenadelauncher.he": 0,
        "ammo.grenadelauncher.smoke": 0,
        "ammo.handmade.shell": 10000,
        "ammo.nailgun.nails": 10000,
        "ammo.pistol": 10000,
        "ammo.pistol.fire": 10000,
        "ammo.pistol.hv": 10000,
        "ammo.rifle": 10000,
        "ammo.rifle.explosive": 10000,
        "ammo.rifle.hv": 10000,
        "ammo.rifle.incendiary": 10000,
        "ammo.rocket.basic": 0,
        "ammo.rocket.fire": 0,
        "ammo.rocket.hv": 0,
        "ammo.rocket.smoke": 0,
        "ammo.shotgun": 10000,
        "ammo.shotgun.fire": 10000,
        "ammo.shotgun.slug": 10000,
        "arrow.bone": 10000,
        "arrow.fire": 10000,
        "arrow.hv": 10000,
        "arrow.wooden": 10000,
        "snowball": 10000,
	"ammo.grenadelauncher.buckshot": 0,
        "ammo.grenadelauncher.he": 0,
        "ammo.grenadelauncher.smoke": 0,
        "ammo.handmade.shell": 10000,
        "ammo.nailgun.nails": 10000,
        "ammo.pistol": 10000,
        "ammo.pistol.fire": 10000,
        "ammo.pistol.hv": 10000,
        "ammo.rifle": 10000,
        "ammo.rifle.explosive": 10000,
        "ammo.rifle.hv": 10000,
        "ammo.rifle.incendiary": 10000,
        "ammo.rocket.basic": 0,
        "ammo.rocket.fire": 0,
        "ammo.rocket.hv": 0,
        "ammo.rocket.smoke": 0,
        "ammo.shotgun": 10000,
        "ammo.shotgun.fire": 10000,
        "ammo.shotgun.slug": 10000,
        "arrow.bone": 10000,
        "arrow.fire": 10000,
        "arrow.hv": 10000,
        "arrow.wooden": 10000,
        "snowball": 10000,
	"bone.fragments": 10000,
        "can.tuna.empty": 10000,
        "cctv.camera": 0,
        "charcoal": 0,
        "cloth": 10000,
        "electric.rf.broadcaster": 10000,
        "electric.rf.receiver": 10000,
        "explosives": 0,
        "fat.animal": 0,
        "gears": 10000,
        "grenade.beancan": 0,
        "gunpowder": 0,
        "ladder.wooden.wall": 10000,
        "leather": 10000,
        "lowgradefuel": 0,
        "metal.fragments": 10000,
        "metal.refined": 10000,
        "metalblade": 10000,
        "metalpipe": 10000,
        "metalspring": 10000,
        "propanetank": 10000,
        "pumpkin": 10000,
        "riflebody": 10000,
        "roadsigns": 10000,
        "rope": 10000,
        "scrap": 10000,
        "semibody": 10000,
        "sewingkit": 10000,
        "sheetmetal": 10000,
        "skull.human": 10000,
        "skull.wolf": 10000,
        "smgbody": 10000,
        "spear.wooden": 10000,
        "stash.small": 10000,
        "stones": 10000,
        "sulfur": 0,
        "syringe.medical": 10000,
        "targeting.computer": 0,
        "tarp": 10000,
        "techparts": 0,
        "wood": 0
      }
    },
    {
      "Name": "craft_all_items_unlimited_ammo",
      "All deployables are free": false,
      "Free deployables": [],
      "Items": {
        "ammo.grenadelauncher.buckshot": 10000,
        "ammo.grenadelauncher.he": 10000,
        "ammo.grenadelauncher.smoke": 10000,
        "ammo.handmade.shell": 10000,
        "ammo.nailgun.nails": 10000,
        "ammo.pistol": 10000,
        "ammo.pistol.fire": 10000,
        "ammo.pistol.hv": 10000,
        "ammo.rifle": 10000,
        "ammo.rifle.explosive": 10000,
        "ammo.rifle.hv": 10000,
        "ammo.rifle.incendiary": 10000,
        "ammo.rocket.basic": 10000,
        "ammo.rocket.fire": 10000,
        "ammo.rocket.hv": 10000,
        "ammo.shotgun": 10000,
        "ammo.shotgun.fire": 10000,
        "ammo.shotgun.slug": 10000,
        "arrow.bone": 10000,
        "arrow.fire": 10000,
        "arrow.hv": 10000,
        "arrow.wooden": 10000,
        "bone.fragments": 10000,
        "can.tuna.empty": 10000,
        "cctv.camera": 10000,
        "charcoal": 10000,
        "cloth": 10000,
        "electric.rf.broadcaster": 10000,
        "electric.rf.receiver": 10000,
        "explosives": 10000,
        "fat.animal": 10000,
        "gears": 10000,
        "grenade.beancan": 10000,
        "gunpowder": 10000,
        "ladder.wooden.wall": 10000,
        "leather": 10000,
        "lowgradefuel": 10000,
        "metal.fragments": 10000,
        "metal.refined": 10000,
        "metalblade": 10000,
        "metalpipe": 10000,
        "metalspring": 10000,
        "propanetank": 10000,
        "pumpkin": 10000,
        "riflebody": 10000,
        "roadsigns": 10000,
        "rope": 10000,
        "scrap": 10000,
        "semibody": 10000,
        "sewingkit": 10000,
        "sheetmetal": 10000,
        "skull.human": 10000,
        "skull.wolf": 10000,
        "smgbody": 10000,
        "snowball": 10000,
        "spear.wooden": 10000,
        "stash.small": 10000,
        "stones": 10000,
        "sulfur": 0,
        "syringe.medical": 10000,
        "targeting.computer": 10000,
        "tarp": 10000,
        "techparts": 0,
        "wood": 0
      }
    }
  ]
}​

Yes, wood:0 is a likely culprit. There is no reason to use that as the permissions don't currently stack (might support that in the future since seems some people want them to stack). I can also make an update to mitigate the kick in case of values less than 1, so that you can have those in the config if you want.