rndr: 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/rndr - from package: Pixie

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

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