Well I actually I finally succeded, when opening an ePub transfered via Calibre.
The kePub always fails loading the plugin while the Calibre ePub always works. But I'm not sure it would have worked if I had not manually set the plugin library in "/usr/local/Kobo" since it was not there after installing it properly.
Many thanks Mrs_Often. :-)
Last edited by Loceka; 01-26-2013 at 02:25 PM.