WordPress MU

Hello :D I'm using htaccess file 3 or 4 months old. The changes I've made are just

From:
RewriteRule ^([_0-9a-zA-Z-]+)/wp-comments-post.php(.*) /wp-inst/wp-comments-post.php [L]

To:
RewriteRule ^([_0-9a-zA-Z-]*)/?wp-comments-post.php(.*) /wp-inst/wp-comments-post.php [L]

And everything worked till some users have started reporting that sometimes they get 404 when they try to comment on some entry. I've done a few experiments and sometimes when I change the entry's name to something simple like "free avatars" to "fa" it works fine. Sometimes when the entry has cyrilic title and content nothing works and there is that 404 error when someone tries to comment.

Oh I almost forgot : when the user is logged in there are no 404 but when he's not they sometimes show up.

God, GOD HEAR ME ! I WANT WPMU TO WORK. AT LEAST THE COMMENTS.. GOD SAVE MY SOUL I WANT TO SLEEP SOMEDAY!!

Try just:

RewriteRule ^wp-comments-post.php /wp-inst/wp-comments-post.php [L]