WordPress MU

I transfered my blogs to a WordPress MU installation several months ago. I just realized today that I have a duplicate content issue - how I have no idea.

There are two versions of many, many posts available. Below is an example:

http://goodplum.com/2008/05/10/what-are-you-passionate-about-2/

and

http://goodplum.com/personal-development/passion/what-are-you-passionate-about-2/

If you look in the source, the canonical link is being set correctly, however - no permalink redirect plugin is working to fix this error, because it's not producing a 404 somehow.

The permalink is set correctly in the database and there isn't a duplicate permalink entry in the database either.

Any ideas?

Is Google itself complaining?

The second link is from your category archives.Pretty common. All you need in your theme is to tell the big G not to follow the archive links. (nofollow on the link in the template)