zone_tool: 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/zone_tool - from package: dms-core

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

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