Contact Us, About Us and API links on the front page have the same problem. If I can't contact you and you're not giving me any info about your site, why should I sign up, giving you my email info?
Even clicking on the Inveni logo on the top of the Signup page doesn't take me to the front page, it just reloads the signup page.
This is really basic stuff that's missing or not working. You sure you're ready to go to Beta yet?
(FF 3.6.13, WinXP SP3)