fedfs-map-nfs4: command not found

Have You tried accessing the binary with the full path?

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/sbin/fedfs-map-nfs4 - from package: fedfs-utils-client

You may install the required package with command yum install {package}
Error in other languages:
fedfs-map-nfs4: bevel nie gevind nie
fedfs-map-nfs4: comandă negăsită
fedfs-map-nfs4: comando não encontrado
fedfs-map-nfs4: commande introuvable
fedfs-map-nfs4: command not found
fedfs-map-nfs4: käsku ei ole
fedfs-map-nfs4: không tìm thấy lệnh
fedfs-map-nfs4: komanda nerasta
fedfs-map-nfs4: Kommando nicht gefunden.
fedfs-map-nfs4: kommandot finns inte
fedfs-map-nfs4: komut yok
fedfs-map-nfs4: nie znaleziono polecenia
fedfs-map-nfs4: níor aimsíodh an t-ordú
fedfs-map-nfs4: no se encontró la orden
fedfs-map-nfs4: no s'ha trobat l'ordre
fedfs-map-nfs4: opdracht niet gevonden
fedfs-map-nfs4: parancs nem található
fedfs-map-nfs4: perintah tidak ditemukan
fedfs-map-nfs4: príkaz nenájdený
fedfs-map-nfs4: příkaz nenalezen
fedfs-map-nfs4: команда не найдена
fedfs-map-nfs4: командата не е открита
fedfs-map-nfs4: 命令找不到
fedfs-map-nfs4: コマンドが見つかりません