maildirmake.maildrop: 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/maildirmake.maildrop - from package: maildrop

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

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