Looks like your theme has some SEO functions built in - Try disabling these from theme settings, clear SuperCache then try Yoast SEO again.
Switching back to default theme - just go to Appearance / Themes and select Twenty Eleven or TwentyTen or TwentyTwelve - They should still be there - in not and someone deleted them, grab a copy of one of these from the theme repository
Sometimes an image or other HTML markup causes this behavior. Don't worry too much about it - as long as your focus keyterm is near the beginning of the first paragraph it's OK...
PS: SEO tip RE H1 markup - Check a published page - the WordPress "Page Title" is usually generated wrapped in H1 markup - You should only ever have a single instance of H1 - H2 is better for a heading in your content.