Ubuntu 7.04/Issues/Broken software index
From DellLinuxWiki
Description: When launching Update Manager, message pops up: "Software index is broken".
Systems Affected: Dimension 530n.
Impact: Can't update any packages using Synaptic Package Manager.
Fix: Run as root:
$ apt-get install -f
Or launch Synaptic Package Manager, select "Broken" from left column, and then select linux-restricted-modules-generic in upper window and click on "Apply" to update package.