Because the board does not have a floppy controller ,to install XP ,you can either switch in BIOS to IDE Mode all the SATA ports ,either use a slipstreamed XP CD .In this last case you can choose between nLite or Xp Iso Builder so you can add the AMD AHCI driver(the one that requires a Floppy ,device non existent on the board).
Even if you choose the IDE Mode you can switch to AHCI later on.For this scenario :install the HDD to one of the 0-3 ports and the CD Rom to one of the 4-5 ports, set the SATA CD Drive port to AHCI mode and let the others on IDE Mode ,install the AMD AHCI driver for the CD Drive via Device Manager ,restart so the driver gets installed and then switch in BIOS all ports to AHCI ,it should work.