Comment 3 for bug 377971

I found the solution for my case:

chmod +x /etc/cron.daily/apt

This broke during the upgrade to Jaunty. The current package has the correct permissions. I have no idea how it went wrong.

I'm reassigning this one to apt, which should be closer to the problem. bdmathias, if this fix doesn't work for you, you should probably open another bug.