rendercheck: 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/rendercheck - from package: rendercheck

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

On Debian possible default full paths are:

/usr/bin/rendercheck - from package: x11-apps

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

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