I had the same problem. After reading your propositions, it still did not work, but it give me some ideas to test.

Note : The error pops up only when choosing the Liberkey Menu folder Icon at the upper left of the applications folder (the other icons choices are : My Menu, Most Recent and Recent).

I FINALLY SOLVED THE DILEMNA :

You've got to restore the Default.xml file to one that has been Bakcuped before the problem happenned. Follow the instructions as follow :

Go to Liberkey/LiberkeyTools/LiberkeyMenu/Data/Menu

There you will find the file Default.xml (rename it ex: Default.xml.ORI to kepp it in case my solution does not work for you.

Now go to the subfolder Bak and make a copy a a Default_xxxxx.xml (where xxxxxx = date of backup) and copy it to the parent directory (Liberkey/LiberkeyTools/LiberkeyMenu/Data/Menu), then rename it Default.xml.

Restrat your Liberkey application and it should work, if not restore the original file tio its original name Defaut.xml.