Thus, since I would not want to spoil my qt installation from ubuntu packages, which is installed in system path, I downloaded the new qt framework 4.6.3 from the Nokia download site, and installed it in a path of my home: ~/usr/local/Trolltech/qtsdk-2010.03.Then, I installed some packages that are useful to build qt-mobility and to enjoy media contents such as mp3 and videos, relying on gstreamer