I recently installed Oneiric, and I am unable to install any software through the software Center, because the Install option is greyed out for everything.
It loads all the software listings alright, but no install button.
apt-get update & apt-get upgrade, enabled everything I saw fit in the software sources, yet no luck.
Installed Synaptic through command line, and it installs packages properly. Since downloaded .deb packages open through the Software Center, I can't install them because install button is greyed out.