ftppass: 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/ftppass - from package: avfs

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

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