rpc.rusersd: 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.rusersd - from package: rusers-server

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

On Debian possible default full paths are:

/usr/sbin/rpc.rusersd - from package: rusersd

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

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