Just built a PC with about the same Spec. My mobo (same) got the CPU speed wrong, I don't know if that can cause problems, check it's right in the BIOS.
Are you using SATA hard drives? I got an error there. You have to find the drivers for SATA that come on the Mobo CD, copy them to floppy, then XP asks foir the drivers that it can't find, and you put the floppy in. (You may need to press an F key while the XP installation starts up)
Otherwise I'd guess there's a read error on the CD-ROM, try another CD drive if you have one.