amavisd-submit: 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/amavisd-submit - from package: amavisd-new

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

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