I get a similar problem. I’ve tried various different combinations, and I just can’t get it to work.
I have the same or very similar problem. I’m running the 1.5 release, with some changes to the templates. Not sure what is causing this.
Warning: comments_template(/home/www/robotiic/wp-content/themes/classic): failed to open stream: Success in /home/www/robotiic/wp-includes/comment-functions.php on line 24
Warning: comments_template(/home/www/robotiic/wp-content/themes/classic): failed to open stream: Success in /home/www/robotiic/wp-includes/comment-functions.php on line 24
Fatal error: comments_template(): Failed opening required '/home/www/robotiic/wp-content/themes/classic' (include_path='.:/usr/local/lib/php') in /home/www/robotiic/wp-includes/comment-functions.php on line 24
