makedat.maildrop: command not found

Have You tried accessing the binary with the full path?

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/makedat.maildrop - from package: maildrop

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