I need to make it so when I step on a turf or area it removes/grants new verbs

This is the Area file

area
arenazone
removeverbs
Entered()
src.verbs -= /mob/verb/create()
src.verbs -= /mob/verb/Fight()
fightzone
Entered()
src.verbs += /mob/verb/Fight()
src.area = "fight zone"
buildzone
Entered()
src.verbs += /mob/verb/create()
src.area = "build zone"

This is the Macro file

mob/verb/Center()
set hidden = 1
if(usr.bob == "fight")fight()
if(usr.bob == "build")create()

here are my errors:

area.dm:5:error:/mob/verb/create:undefined type path
area.dm:13:error:/mob/verb/create:undefined type path
area.dm:6:/mob/verb/Fight:warning: use call() to call a proc by reference
area.dm:10:error:src.area:undefined var
area.dm:9:/mob/verb/Fight:warning: use call() to call a proc by reference
area.dm:14:error:src.area:undefined var