You sure that this bios for your MoBo ? Try to flash the original (sp35159.exe) bios before. Then rename 507_SLIC.ROM to 507.ROM and right click on WINFLASH.EXE (from original pack) and RUN AS ADMINISTRATOR and follow on-screen instructions.
I retract my request. I modded the bios myself, it was a piece of cake. Took about 20 min. Thanks anyway! And thanks for AMITool!