The blog linked to your username is a free blog being free hosted by WordPress.com.
There is no FTP access to free hosted WordPress.COM blogs for security reasons and we cannot upload themes into them. The only themes we can use are located here > Appearance > Themes
Thesis is a paid theme that can only be used on WordPress.ORG installs for self-hosting. Please read this entry so you are clear on the differences between the two. WordPress.com vs. WordPress.org: The Differences WordPress.com vs. WordPress.org
If you are asking about a self-hosted WordPress.ORG install then know this there is not support to be found here at WordPress.COM for self hosted installs. You must post to http://wordpress.ORG/support to get support for self-hosted WordPress.ORG installs.