NEED MAJOR HELP! check out this error code

So after tweaking code for hours to get my static page up and adding a new page template to my ftp. I also changed the header image link to the blog that way it doesn’t link back to the static page every time. I finally finish everything and next thing you know when you click on any post I get this error. also if you want try yourself

http://www.yungproblem.com

Warning: include(/home/mediat26/public_html/yungproblem.com/wp-content/themes/Backstreet/) [function.include]: failed to open stream: No such device in /home/mediat26/public_html/yungproblem.com/wp-includes/template-loader.php on line 43

Warning: include() [function.include]: Failed opening ‘/home/mediat26/public_html/yungproblem.com/wp-content/themes/Backstreet/’ for inclusion (include_path=’.:/usr/lib/php:/usr/local/lib/php’) in /home/mediat26/public_html/yungproblem.com/wp-includes/template-loader.php on line 43