zzdir: 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/zzdir - from package: zziplib-bin

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

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