usbprog-gui: 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/usbprog-gui - from package: usbprog-gui

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

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