[SOLVED] Google Crawl Error

I just enabled Google's Webmaster Tools and received a "404 (Not Found)" crawl error, and I would appreciate some help fixing the error.

The URL that is creating the error is http://www.mydomain.com/posts/%post_name/

When I click on that URL, I reach a page whose body reads, "Not Found. Sorry, but you are looking for something that isn't here."

The "Links From Detected" are:

http://mydomain.com/posts/category/uncategorized/
http://www.mydomain.com/posts/category/uncategorized/
http://www.mydomain.com/sitemap.xml.gz

When I click on the first two of these URLs, I reach a page whose body reads, "Not Found. Sorry, but you are looking for something that isn't here."

I have no posts on my site—just static pages—so I suspect that this may be contributing to the problem.

One thing that confuses me is this: when I look at my sitemap at http://www.mydomain.com/sitemap.xml, http://www.mydomain.com/posts/%post_name/ is not listed—only the static pages are listed, so I don't understand why Google is detecting a link from http://www.mydomain.com/sitemap.xml.gz to http://www.mydomain.com/posts/%post_name/.

I just updated to WordPress 3.1 and Atahualpa 3.6.4, but the error existed prior to the update.

I am also using the following potentially relevant plugins: Google XML Sitemaps and All in One SEO Pack. I don't know whether the settings on either of these plugins might be creating the problem or be able to solve the problem, but I thought I'd mention them just in case.

Please help. Thanks!