gbx3: 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/gbx3 - from package: gambas3-runtime

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

Error in other languages:
gbx3: bevel nie gevind nie
gbx3: comandă negăsită
gbx3: comando não encontrado
gbx3: commande introuvable
gbx3: command not found
gbx3: käsku ei ole
gbx3: không tìm thấy lệnh
gbx3: komanda nerasta
gbx3: Kommando nicht gefunden.
gbx3: kommandot finns inte
gbx3: komut yok
gbx3: nie znaleziono polecenia
gbx3: níor aimsíodh an t-ordú
gbx3: no se encontró la orden
gbx3: no s'ha trobat l'ordre
gbx3: opdracht niet gevonden
gbx3: parancs nem található
gbx3: perintah tidak ditemukan
gbx3: príkaz nenájdený
gbx3: příkaz nenalezen
gbx3: команда не найдена
gbx3: командата не е открита
gbx3: 命令找不到
gbx3: コマンドが見つかりません