fatmen: 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/fatmen - from package: cernlib-packlib

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

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