amavisd-nanny: 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 CentOS possible default full paths are:

/usr/bin/amavisd-nanny - from package: amavisd-new

You may install the required package with command yum install {package}

On Debian possible default full paths are:

/usr/sbin/amavisd-nanny - from package: amavisd-new

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

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