gummi: 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/gummi - from package: gummi

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

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