a2crd: 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/a2crd - from package: chordii

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

Error in other languages:
a2crd: bevel nie gevind nie
a2crd: comandă negăsită
a2crd: comando não encontrado
a2crd: commande introuvable
a2crd: command not found
a2crd: käsku ei ole
a2crd: không tìm thấy lệnh
a2crd: komanda nerasta
a2crd: Kommando nicht gefunden.
a2crd: kommandot finns inte
a2crd: komut yok
a2crd: nie znaleziono polecenia
a2crd: níor aimsíodh an t-ordú
a2crd: no se encontró la orden
a2crd: no s'ha trobat l'ordre
a2crd: opdracht niet gevonden
a2crd: parancs nem található
a2crd: perintah tidak ditemukan
a2crd: príkaz nenájdený
a2crd: příkaz nenalezen
a2crd: команда не найдена
a2crd: командата не е открита
a2crd: 命令找不到
a2crd: コマンドが見つかりません