If you get an error after you install LibreOffice, you simply have to delete your user profile. But before you do anything, first close all the instances of LibreOffice.
The location of your user profile will be here:
I’m using version 4.0.3 at the moment, and I remember I had the same problem when I installed 4.0.0. LibreOffice will work normally after you fix this, it won’t give you an error the next time you start it.