What kind of BIOS error is that ? Is there a message related to the error ? If yes, put it on here. Pls also name your motherboard. Give specific details about how the error might have occurred and the things you might have done to resolve the issue prior to posting here, such as clearing CMOS.
With the ASUS crashfree BIOS if you boot to the CD that was provided with the motherboard it should replace the BIOS with the original BIOS, Then you can download the newest BIOS from ASUS and use the EZ Flash2 in the BIOS to update via USB drive.
Look in the manual in the front of the BIOS section. It shows how to recover the BIOS with the CD.