kftp: 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/kftp - from package: heimdal-clients

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

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