I think englandr hit it on the head.. your board may support that cpu, however, it may require a bios update first. do you have an older cpu that you could throw in there to update the bios? If memory serves me right, that is a 45nm cpu.. in which case there is a bios update for compatibility with those cpus.. here is the link to the bios download page... let us know if this works
http://www.uabit.com/index.php?option=com_content&task=view&id=32&Itemid=48&page=3&model=381