mzclient: 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 Debian possible default full paths are:

/usr/bin/mzclient - from package: mzclient

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

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