I give up...please help regarding wp-login.php redirect

Okay, I don't believe in begging for help until I've given it my best, and I throw myself on the mercy of the forum! I need your help.

I'm using Revolution Magazine, slightly modified, but nothing too fancy.

Here's my site: http://SixStringReview.com

I have put a lot of work into this puppy, and it's finally starting to pick up some traffic, but I was surprised that I didn't have a single comment on any of the posts yet. Nothing.

So, I went to try a sample post, and I get the "Not Found, Error 404" message when I click on any "You must be logged in to post a comment" link.

I can, of course, turn off the requirement for people to be registered, but I prefer not to do so.

I changed to other themes I have installed, and they all redirect to the login page just fine.

FYI, I uploaded a fresh version of the Magazine 3.0 theme to test, and it does the same thing.

Any advice?