olfilter: 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/olfilter - from package: ladr4-apps

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

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