Hi,
I had the same issue. After setting up SEO MOZ, fixing about 400 problems, on the next crawl (after installing wordpress and transfering all our old news items across for our blog) we had about 1,000 problems with duplicate pages (most blog pages were duplicated 50 times!!!.
I've installed Yoast, had a quick go through (looks good), I think I've got it sorted 
I'll check again after the next crawl and see if it works and report back.
It's interesting how this question is also asked in the Wordpress forums with no responses or silly comments about SEOMOZ being rubbish and not understanding how Wordpress works (or what not).
