RHEL 5 installation

[willa]

Hi everyone, I m new here and I have few questions regarding RHEL installation. The story goes like this...
I have a PC with the following specifications:
1. ASUS P5N-MX motherboard with on-board GForce 7050/nforce 610i chipset
2. Intel Pentium Dual Core Processor
3. Two SATA HDD(250GB + 160GB)
4. DDR2 4GB RAM

Currently I am running Win XP together with FC8(dual boot). I want to install RHEL 5 on my system. I used an installation DVD, the process went on fine from beginning until I reached a point where I am supposed to specify the location on which to install. I chose custom partition as I already have other OSs on my system, then after clicking next I got an error message specifying that redhat could not find disk on which to install and advised me to check my hardware. I know my hardware is just fine because the other OSs are working just fine so I need a help on how I can perform this installation on SATA HDD.