Serious problem. Help?

Hello, I recently checked my WordPress site and it gave me this: `Warning: require(/homepages/3/d321317101/htdocs/wp-includes/comment.php) [function.require]: failed to open stream: Permission denied in /homepages/3/d321317101/htdocs/wp-settings.php on line 116

Fatal error: require() [function.require]: Failed opening required ‘/homepages/3/d321317101/htdocs/wp-includes/comment.php’ (include_path=’.:/usr/lib/php5′) in /homepages/3/d321317101/htdocs/wp-settings.php on line 116`

What the heck happend here? http://nicks-blog.net/
I did recently look in my webspace and there were two hacks 9.txt and ah.txt. One said hacked by hacktohack. The other said some crap about “This is only educational.” I deleted these promptly. Did these have something to do with the current state of my blog?