metacity-message: command not found

Maybe Your $PATH variable doesn't contain the default paths? echo $PATH should give something like:

[root@server ~]# echo $PATH
/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin

If it's empty, You may set the PATH variable with this command

export PATH="/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin"

On CentOS possible default full paths are:

/usr/bin/metacity-message - from package: metacity

You may install the required package with command yum install {package}

On Debian possible default full paths are:

/usr/bin/metacity-message - from package: metacity

You may install the required package with command apt-get install {package}

Error in other languages:
metacity-message: bevel nie gevind nie
metacity-message: comandă negăsită
metacity-message: comando não encontrado
metacity-message: commande introuvable
metacity-message: command not found
metacity-message: käsku ei ole
metacity-message: không tìm thấy lệnh
metacity-message: komanda nerasta
metacity-message: Kommando nicht gefunden.
metacity-message: kommandot finns inte
metacity-message: komut yok
metacity-message: nie znaleziono polecenia
metacity-message: níor aimsíodh an t-ordú
metacity-message: no se encontró la orden
metacity-message: no s'ha trobat l'ordre
metacity-message: opdracht niet gevonden
metacity-message: parancs nem található
metacity-message: perintah tidak ditemukan
metacity-message: príkaz nenájdený
metacity-message: příkaz nenalezen
metacity-message: команда не найдена
metacity-message: командата не е открита
metacity-message: 命令找不到
metacity-message: コマンドが見つかりません