rpc.ypxfrd: 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.ypxfrd - from package: ypserv

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

On Debian possible default full paths are:

/usr/sbin/rpc.ypxfrd - from package: nis

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

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