gbackground: 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/gbackground - from package: gbackground

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

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