fetch_file: 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/fetch_file - from package: python2-boto
/usr/bin/fetch_file - from package: python-boto

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

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