Google Web Master Tools: Increase in not found errors

Hi everyone,

A few days ago I received a message in Webmaster Tools that my site has increase in 404 errors.

I noticed that all the crawl errors are related to images.

The URL is like ?attachment_id=416 (http://screencast.com/t/06RX5EA9S0).

When i click on the error details, it says it is linking from the sitemap.xml.gz. When I open the Sitemap, it is not there. The Sitemap only shows the URL of posts and pages but not attachments.

When I click on the error URL it loads the attachment (image). It redirects from http://www.clifftam.com/?attachment_id=416 to
http://www.clifftam.com/use-less-internet-bandwidth-windows-7/firefox-disable-share-data/

I suspect this is the problem.

Has anyone experience this and how to fix it? How do i set it up such that when Google crawls my site, it goes to the friendly URL and not the one with id=XXX?

I am using WP (3.9.2) with All in One SEO (2.2.2).

Thanks!
Cliff