amavisd-release: 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 CentOS possible default full paths are:

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

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