Old versions of BackInTime (< 1.1.0) where a bit tricky if you want to restore files on a different machine (with different host/user name). Please install the current version from our PPA. This is much more user friendly. It comes with a restore function for the config and won't need to trick the host/user name anymore.
Open a Terminal with CTRL+ALT+T and type:
sudo add-apt-repository ppa:bit-team/stable
sudo apt-get update
sudo apt-get install backintime-qt4
Now you can either restore the old config with the Restore Config
button in Settings or just delete the current config (rm ~/.config/backintime/config
in Terminal). BackInTime will automatically search for the old config on next start.