1. Frequently get the following error message: 1.1. "Nepomuk Semantic Desktop needs the Virtuoso RDF server to store its data. Installing the Virtuoso Soprano plugin is mandatory for using Nepomuk.". 1.2. If the Nepomuk Semantic Desktop needed any additional components for its proper functioning, these should have been provided during the installation of Kubuntu 12.04.
This issue shall be reported to Ubuntu.