gbc3: 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/gbc3 - from package: gambas3-dev

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

Error in other languages:
gbc3: bevel nie gevind nie
gbc3: comandă negăsită
gbc3: comando não encontrado
gbc3: commande introuvable
gbc3: command not found
gbc3: käsku ei ole
gbc3: không tìm thấy lệnh
gbc3: komanda nerasta
gbc3: Kommando nicht gefunden.
gbc3: kommandot finns inte
gbc3: komut yok
gbc3: nie znaleziono polecenia
gbc3: níor aimsíodh an t-ordú
gbc3: no se encontró la orden
gbc3: no s'ha trobat l'ordre
gbc3: opdracht niet gevonden
gbc3: parancs nem található
gbc3: perintah tidak ditemukan
gbc3: príkaz nenájdený
gbc3: příkaz nenalezen
gbc3: команда не найдена
gbc3: командата не е открита
gbc3: 命令找不到
gbc3: コマンドが見つかりません