I've installed Debian on 4 different PowerEdge servers now, without any problems. I had to use Etch, to get a recent enough kernel to support the SATA controller. Other than that, everything was fine.
However, I haven't installed on your particular model. Looking at the specs, there are a few different hard drive controller options available. Which one do you have? If it's an add-on card, do you know the model? If it's the integrated controller, do you know the chipset? -- Kevin