Reading about the next build and the fact that it is not compatible with windows XP. My question is if Windows Web Server 2008 R2 will run rf2?
Whatever you're using, just google the kernel it's using. If it's XP based or an XP derivative (or became one) then it's not going to run.
If you notice on those lists, Windows XP x64 was not a 64-bit version of Windows XP. It was Windows Server 2003 x64 with an XP UI (Both used Kernel NT 5.2) XP was the last time MS used a different kernel for server and client. Beginning with Windows Vista, both server and client share the same kernel.