Because it is a VERY VERY old edition and there is some restriction about the disk.
Red Hat limited the ext3 partition must be the first place of the physical hard disk NO larger than 2GB . Otherwise you can not boot the Red Hat 9 at all!
I suggest you to change to a newer edition to install.
to see the support of your hard ware, 国外的一个网站:http://www.linux-laptop.net
搜罗了很多有关电脑硬件及其所支持的linux发行版本,很全。