clean-crl: 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 CentOS possible default full paths are:

/usr/sbin/clean-crl - from package: fetch-crl

You may install the required package with command yum install {package}

On Debian possible default full paths are:

/usr/sbin/clean-crl - from package: fetch-crl

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

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