I tried to get FC3 to install on my basement Gentoo box today, and it popped up error messages about failure to probe partition geometry. I have to presume this is an attempt by RedHat's proprietary formatting tool to understand the partitions on my main hard drive. These were created by fdisk (2.12i), which is a pretty standard tool.
Gentoo hasn't had any trouble working with the disk, and I'm not sure why Fedora would, but it won't complete the install.
I imagine it might work if I used gentoo's fdisk to delete all the partitions, but I want to keep the main partition (/) which has a lot of data on it.
I guess I can just wait for FC4 to make it out, but it's frustrating. RH used to offer to allow you to use cfdisk or fdisk (I forget) instead of it's proprietary formatter, which never did work worth a darn.