rpc.mountd: 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/sbin/rpc.mountd - from package: nfs-utils

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

On Debian possible default full paths are:

/usr/sbin/rpc.mountd - from package: nfs-kernel-server

You may install the required package with command apt-get install {package}

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