arden-filter: 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/arden-filter - from package: arden

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

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