wp-comments-post.php problem? 405

related thread I’ve reviewed: http://wordpress.org/support/topic/151072

When comments are written to http://www.obrienstore.com, they get submitted but the user gets a 405 or blank page.

WordPress is installed at http://www.obrienstore.com and the blog homepage is set as http://www.obrienstore.com
BUT I do have the front page set to a static page and the Posts page set to http://www.obrienstore.com/blarney-social-club/ – I can’t discern if that is causing the problem.

I tried changing the blog address to http://www.obrienstore.com/blarney-social-club/ and that worked BUT then my blog homepage is http://www.obrienstore.com/blarney-social-club/blarney-social-club/ which is awful, and each post lives in the /blarney-social-club/ directory which I really don’t want as it makes the URLs way too long.

I’m at a loss. I can’t figure out what tearooms comment in that other thread is suggesting I try. It looks like I can have the comment-post look in the directory for the blog but I don’t understand how.

Appreciate the help!!!