Hi Falko,
After sending you my earlier email I decided to do some more investigating of the new icon that appeared on my desktop with the text:/home/ernest/Desktop/OOO300_m9_native_packed-1_en-US.9358 On clicking on to this icon four other icons appeared one of which had the text
ebs which in turn led me another icon-titled: desktop- integration. and then:/home/ernest/Desktop/OOO300_m9_native_packed-1_en-US.9358/DEBS/desktop-integration/openoffice.org3.0-debian-menus_3.0-9354_all.deb.Clicking on this opened the Package installer-openoffice.org-debian-menus with this message in red against Status: Conflicts with the installed package 'openoffice.org-core'
I trust that this might be of some help to you in solving the problem of trying to install the Version 3.0.0 alongside the installed one.
Ernest.