Comment 9 for bug 1100992

That's odd. For example, there's no gnome-icon-theme-symbolic in Ubuntu 10.04 archives at all. And those packages in Lucid shouldn't break on those mentioned in the error messages.

If you're sure you haven't installed any third party packages (please check whether there's something mentioned in Software Properties -> Other Software list), there's nothing else I could think of. Let's hope someone else has some idea what's going on here...