cd5: 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/cd5 - from package: cd5

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

Error in other languages:
cd5: bevel nie gevind nie
cd5: comandă negăsită
cd5: comando não encontrado
cd5: commande introuvable
cd5: command not found
cd5: käsku ei ole
cd5: không tìm thấy lệnh
cd5: komanda nerasta
cd5: Kommando nicht gefunden.
cd5: kommandot finns inte
cd5: komut yok
cd5: nie znaleziono polecenia
cd5: níor aimsíodh an t-ordú
cd5: no se encontró la orden
cd5: no s'ha trobat l'ordre
cd5: opdracht niet gevonden
cd5: parancs nem található
cd5: perintah tidak ditemukan
cd5: príkaz nenájdený
cd5: příkaz nenalezen
cd5: команда не найдена
cd5: командата не е открита
cd5: 命令找不到
cd5: コマンドが見つかりません