I just did a fresh install of 1.5.3 and everything worked fine. I installed the hyperion template with the same results.
I was in the process of adding sections, categories, articles, and modifying the main menu when I hit the preview button and was given a 404 error code for the main page.
Up until this point everything has been working fine including the main page. I can log into and out of the administrator page with ease. No issues what so ever.