The first time I downloaded the Release Preview from the Release Preview page and started the install it showed the vista boot screen when booting and then showed the same screen as you have. (can you confirm this?)
Just tried that and didn't work. I tried the Consumer Preview install ISO and that works fine. SO yeah, this sucks.
I re-downloaded the ISO and now it shows a black boot screen named 'Windows'. This time it goes directly to 'Enter the product key' window.
I downloaded both ISO's from the same page.
 I'm installing this in vmware fusion.