FileFilter: 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/FileFilter - from package: topp

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

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