metacity: 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 - from package: metacity

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

On Debian possible default full paths are:

/usr/bin/metacity - from package: metacity

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

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