chmod: 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:

/bin/chmod - from package: coreutils

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

On Debian possible default full paths are:

/bin/chmod - from package: coreutils

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

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