Group Manager Error?

Hi, I've been encountering this error ever since I last changed my groups.yml. I have multiverse and therefore have different world folders in groupmanager. It says there is an error with the line 'build: true' but I can't see anything wrong! Maybe you can help:

=============================== GM ERROR LOG ===============================
= ERROR REPORT START - 2.1.28 (Phoenix) =

java.lang.IllegalArgumentException: The following file couldn't pass on Parser.
plugins\GroupManager\worlds\world\groups.yml
at org.anjocaido.groupmanager.dataholder.WorldDataHolder.loadGroups(WorldDataHolder.java:590)
at org.anjocaido.groupmanager.dataholder.WorldDataHolder.loadGroups(WorldDataHolder.java:510)
at org.anjocaido.groupmanager.dataholder.worlds.WorldsHolder.loadWorld(WorldsHolder.java:678)
at org.anjocaido.groupmanager.dataholder.worlds.WorldsHolder.loadWorld(WorldsHolder.java:640)
at org.anjocaido.groupmanager.dataholder.worlds.WorldsHolder.initialWorldLoading(WorldsHolder.java:110)
at org.anjocaido.groupmanager.dataholder.worlds.WorldsHolder.initialLoad(WorldsHolder.java:100)
at org.anjocaido.groupmanager.dataholder.worlds.WorldsHolder.resetWorldsHolder(WorldsHolder.java:92)
at org.anjocaido.groupmanager.dataholder.worlds.WorldsHolder.<init>(WorldsHolder.java:59)
at org.anjocaido.groupmanager.GroupManager.onEnable(GroupManager.java:179)
at org.anjocaido.groupmanager.GroupManager.onEnable(GroupManager.java:103)
at org.bukkit.plugin.java.JavaPlugin.setEnabled(JavaPlugin.java:316)
at org.bukkit.plugin.java.JavaPluginLoader.enablePlugin(JavaPluginLoader.java:324)
at us.Myles.PWP.TransparentListeners.PerWorldPluginLoader.enablePlugin(PerWorldPluginLoader.java:145)
at org.bukkit.plugin.SimplePluginManager.enablePlugin(SimplePluginManager.java:404)
at org.bukkit.craftbukkit.v1_7_R4.CraftServer.loadPlugin(CraftServer.java:455)
at org.bukkit.craftbukkit.v1_7_R4.CraftServer.enablePlugins(CraftServer.java:389)
at net.minecraft.server.v1_7_R4.MinecraftServer.n(MinecraftServer.java:352)
at net.minecraft.server.v1_7_R4.MinecraftServer.g(MinecraftServer.java:326)
at net.minecraft.server.v1_7_R4.MinecraftServer.a(MinecraftServer.java:282)
at net.minecraft.server.v1_7_R4.DedicatedServer.init(DedicatedServer.java:189)
at net.minecraft.server.v1_7_R4.MinecraftServer.run(MinecraftServer.java:436)
at net.minecraft.server.v1_7_R4.ThreadServerApplication.run(SourceFile:628)
Caused by: mapping values are not allowed here
in "<reader>", line 73, column 12:
build: true
^