phing: 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/phing - from package: php-pear-phing

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

On Debian possible default full paths are:

/usr/bin/phing - from package: phing

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

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