xrdstagetool: 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/xrdstagetool - from package: xrootd-client

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

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