Dave,  This is an issue with the age of the OMSA disk. . Would you download the Poweredge SC Server Installation disk located here -  support.dell.com/.../download.aspx Let me know if you have any issues. 
I am trying to install Small Business Server 2003 on an SC420 using the OMSA install disk that came with the server, but it keeps failing. It copies the info from the OMSA disk, then asks for the SBS Disk 1, and copies all the info from there, but when the Windows instal reboots the server, it says "File amdide.sys not found. Press any key to continue." When I press any key, it says "Install failed. Press any key to reboot." What is amdide.sys (the server has an Intel processor and an Intel chipset for graphics) and why is the OMSA installer not providing it? I thought that was the reason for using OMSA, so it would be sure to install all the needed drivers. Does anyone have any ideas what else I need to do to install this older OS o an older server? It had previously been running Server 2000, but the OMSA installer lists SBS 2003 as a selectable OS. Thanks for any help, Dave
OS install fails on SC420 w/ OMSA