ftpscrub: 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/ftpscrub - from package: proftpd

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

On Debian possible default full paths are:

/usr/sbin/ftpscrub - from package: proftpd-basic

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

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