scmail-deliver: 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/scmail-deliver - from package: scmail

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

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