SBEP Flak Cannon Error

sv: Wire error (Entity [799][sf-flakcannon]):
lua/entities/sf-flakshell/init.lua:20: attempt to call field 'registerent' (a nil value)
stack traceback:
	lua/entities/sf-flakshell/init.lua:20: in function 'Initialize'
	lua/entities/sf-flakcannon/init.lua:102: in function 'HPFire'
	lua/entities/sf-flakcannon/init.lua:59: in function <lua/entities/sf-flakcannon/init.lua:54>
	[C]: in function 'xpcall'
	addons/wire/lua/wire/server/wirelib.lua:62: in function 'TriggerInput'
	addons/wire/lua/wire/server/wirelib.lua:527: in function 'Wire_TriggerOutput'
	addons/wire/lua/entities/gmod_wire_input.lua:76: in function 'func'
	lua/includes/modules/numpad.lua:86: in function 'FireImpulse'
	lua/includes/modules/numpad.lua:114: in function 'Activate'
	gamemodes/spacebuild3/gamemode/player.lua:212: in function <gamemodes/spacebuild3/gamemode/player.lua:210>