This problem is not critical and is just a matter of the configuration file probably containing values that should have been written differently. You don't need to do anything as it's not going to affect your usage of the program.
It is also probable that this only happens because you are using LibreOffice from the Document Foundation (built for any Debian system) and not for Ubuntu specifically (and thus having any Ubuntu-specific patches). Ubuntu builds (such as those in the LibreOffice PPA) would have any changes needed to run on Ubuntu already built in.
By the way, I would suggest using this PPA or waiting for newer versions to land in the default repos rather than using the "normal" builds for the above mentioned reason. LibreOffice 4.0 is included in Ubuntu 13.04, so if you are on 12.04 or 12.10, chances are it will come downstream to you as well in the not-so-far future.