grdesktop: 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/grdesktop - from package: grdesktop

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

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