gurlchecker: 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 Debian possible default full paths are:

/usr/bin/gurlchecker - from package: gurlchecker

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

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