GroupManager Prefixes Help

On my bukkit server when i want to add this prefix [Admin} when an admin talks i already have the group but when i go o my server the prefix never works this is what i typed can someone please help

Admin:
default: false
permissions: []
inheritance:
- moderator
- g:groupmanager_admin
- g:bukkit_admin
- g:essentials_admin
- g:towny_admin
- g:vanish_admin
info:
prefix: '&2[Admin]'
build: true
suffix: ''

 

here's how mines set up i hope it helps in some way or form

Code:

groups:
  Default:
    default: true
    permissions:
    - -bukkit.command.kill
    - warp.sign.to.defualt
    - xwarp.warp.sign.to.default
    inheritance:
    - g:essentials_default
    - g:bukkit_default
    info:
      prefix: '&b[&eUnverifyed&b]&f-'
      build: true
      suffix: ''
  Owner:
    default: false
    permissions:
    - '*'
    inheritance:
    - admin
    info:
      prefix: '&b[&3Owner&b]&f-'
      build: true
      suffix: ''
  Co-Owner:
    default: false
    permissions:
    - '*'
    inheritance:
    - admin
    info:
      prefix: '&b[&9Co-Owner&b]&f-'
      build: true
      suffix: ''
  Builder:
    default: false
    permissions: []
    inheritance:
    - default
    - g:essentials_builder
    - g:towny_moderator
    info:
      prefix: '&b[&2Builder&b]&f-'
      build: true
      suffix: ''
  Moderator:
    default: false
    permissions:
    - worldedit.wand
    inheritance:
    - builder
    - g:essentials_moderator
    - g:bukkit_moderator
    - g:towny_moderator
    info:
      prefix: '&b[&5Moderator&b]&f-'
      build: true
      suffix: ''
  Admin:
    default: false
    permissions:
    - essentials.balance
    - essentials.ban
    - essentials.banip
    - essentials.eco
    - essentials.pay
    - essentials.sell
    inheritance:
    - moderator
    - g:essentials_admin
    - g:bukkit_admin
    - g:towny_admin
    info:
      prefix: '&b[&2Admin&b]&f-'
      build: true
      suffix: ''

 

i set it up just like that and still it didnt work