Bukkit

Per World Permission does not work for me, why?
I want all users in the first "start" world and the "city" world not have the ability to build.
I then want all users in the "wild" world to have the ability to build in!
Whats wrong? The config or some bug?

I use:
Craftbukkit DEV (1.4.6-R0.4 #2590)
Multiverse-Core v2.4-b527
PlotMe v0.12
PermissionsBukkit v2.0

My PermissionsBukkit/config.yml file:
users:
  ConspiracyWizard:
    permissions:
      permissions.example: true
    groups:
    - admin
groups:
  default:
    permissions:
      multiverse.teleport.self.*: true
      plotme.use: true
      bukkit.command.ban: false
      bukkit.command.op: false
    worlds:
      start:
        permissions.build: false
      wild:
        permissions.build: true
      city:
        permissions.build: false
  admin:
    permissions:
    inheritance:
    - user
  user:
    permissions:
      permissions.build: true
    worlds:
      creative:
        coolplugin.item: true
    inheritance:
    - default
messages:
  build: '&cYou do not have permission to build here.'
debug: false