SEO question

I am doing seo On my wordpress install and i am using a third party seo app.to do my seo(SEOMoz)after it crawls my site, its crawl tool (rogerbot)says there is a bunch of errors on my blog site,specifically,my posts.the errors it found are duplicate page content,duplicate title content.errors of that sort of nature.When going in to my ftp folder where my blog resides I cant find where my posts are(the html files) so I can fix the errors.How can I go about doing this?I cant for the darndest figure this one out 🙁 I should probably point out that my WP blog is a free blog.Could anyone help?

Thanks so much in advance

Shawn