zephyrd: 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/zephyrd - from package: zephyr-server-krb5
/usr/sbin/zephyrd - from package: zephyr-server

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

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