xrdmapc: 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/xrdmapc - from package: xrootd-server

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

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