autoupdate: 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/autoupdate - from package: autoconf

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

On Debian possible default full paths are:

/usr/bin/autoupdate - from package: autoconf

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

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