Liberkey is much better than LupoPensuite or PortableApps
All the settings for Liberkey Menu are stored in xml files in folder "LiberkeyTools" in the root directory where you installed Liberkey. Just copy the whole folder and back it up in a safe place.
If you are looking for specific xml files, then here is a breakdown:
..\Liberkey\LiberkeyTools\LKConfig.xml - General settings (username password, language etc)
..\LiberKey\LiberKeyTools\LiberKeyMenu\data\user_prefs.xml - Menu Preferences
..\\LiberKey\LiberKeyTools\LiberKeyMenu\data\Menu\myapps.xml - Application list in MyApps Menu
..\\LiberKey\LiberKeyTools\LiberKeyMenu\data\Menu\default.xml - Application list in Liberkey Menu