Your motherboard is getting confused by the fact that you're running an XP-M mobile CPU. ABIT's website doesn't explicitly mention whether that motherboard supports an XP-M. Have you tried updating your motherboard BIOS? You'll have to be able to boot DOS to try it (unless you have another Athlon XP laying around). The default CPU multiplier is 6 and the motherboard has apparently set the FSB to 100MHz because it doesn't recognize the CPU.
If you can't boot DOS in its current condition can you get into the BIOS? If so then you can probably set the FSB, CPU voltage, and CPU multipler manually so the CPU will work at its rated speed (or beyond - your multiplier is unlocked). An XP-M operates as a plain old XP Barton on motherboards which allow you to set everything manually.
If you can't boot DOS in its current condition can you get into the BIOS? If so then you can probably set the FSB, CPU voltage, and CPU multipler manually so the CPU will work at its rated speed (or beyond - your multiplier is unlocked). An XP-M operates as a plain old XP Barton on motherboards which allow you to set everything manually.