i7z_GUI: 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/sbin/i7z_GUI - from package: i7z-gui

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

Error in other languages:
i7z_GUI: bevel nie gevind nie
i7z_GUI: comandă negăsită
i7z_GUI: comando não encontrado
i7z_GUI: commande introuvable
i7z_GUI: command not found
i7z_GUI: käsku ei ole
i7z_GUI: không tìm thấy lệnh
i7z_GUI: komanda nerasta
i7z_GUI: Kommando nicht gefunden.
i7z_GUI: kommandot finns inte
i7z_GUI: komut yok
i7z_GUI: nie znaleziono polecenia
i7z_GUI: níor aimsíodh an t-ordú
i7z_GUI: no se encontró la orden
i7z_GUI: no s'ha trobat l'ordre
i7z_GUI: opdracht niet gevonden
i7z_GUI: parancs nem található
i7z_GUI: perintah tidak ditemukan
i7z_GUI: príkaz nenájdený
i7z_GUI: příkaz nenalezen
i7z_GUI: команда не найдена
i7z_GUI: командата не е открита
i7z_GUI: 命令找不到
i7z_GUI: コマンドが見つかりません