backintime: command not found

Have You tried accessing the binary with the full path?

Maybe Your $PATH variable doesn't contain the default paths? echo $PATH should give something like:

[root@server ~]# echo $PATH

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 - from package: backintime-common

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