backintime-gnome: 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/backintime-gnome - from package: backintime-gnome

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

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