atftpd: 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/sbin/atftpd - from package: atftpd

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

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