Back to what you said about the IDE driver, might it be related to something I'm doing wrong with the RAID?
Huh? RAID? First mention of such . . . as I seem to recall. That could well be an issue. If there is not a true hardware RAID controller in the system, then you would be advised to use the Linux kernel software RAID and not a BIOS / fake RAID. A search through past forum posts will show that the attempted usage of a BIOS / fake RAID is the source of considerable problems, confusion and data loss. (BIOS / fake RAIDs are only of relevance in the Redmond 'Doze OS environment).
As for two 4 GB hard disks -- are you sure of their capacity? Could they actually be 40 GB? I wouldn't consider attempting to install on a disk smaller than 25 GB -- even if pushed and would consider 40 GB to be the viable minimum for a workstation, not a server.
when I check the DVD for errors it says there's something wrong
How are you checking? After booting the DVD, by selecting the media check option?
Again, the information you have provided is pointing back to the BIOS, BIOS configuration or the disk controller.