I hit a weird bug today when trying to install Longhorn Server Beta 3 on a new box I just built for that purpose. I put in a Highpoint RocketRaid 2310 RAID controller set up with three 500GB SATA drives in RAID5 on an Intel D945GTP motherboard.
I booted up the PC into the Longhorn DVD and started the installation process. As expected once I got to the drive selection screen nothing showed up. I inserted my USB Flash drive with the Highpoint RAID controller driver on it and chose Load Driver. Then from there I navigated to the flash drive and to the drivers I copied to it. After choosing the right driver for my setup, the Longhorn setup now found my RAID drive. However, when I clicked on Next, instead of moving to the next screen, I was greeted with a wonderful error:
Windows is unable to find a system volume that meets its criteria for installation
Nice! Well to cut a long story short, after a bunch of fiddling around it turns out that in order to get past this to install Longhorn Server you have to go back into your BIOS, change the hard drive to be the first drive and first device in the boot order (so move it before the DVD drive and/or any LAN cards) and try running setup again.
On the second time around, do exactly the same as the first time, insert the flash drive, load the driver and then select the newly discovered RAID drive. This time around hitting Next will take you to the next installation screen and you should be good to go. Weird, huh?