gxkb: 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/gxkb - from package: gxkb

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

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