updatedb: 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/updatedb - from package: mlocate

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

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