nope a logic board failure is quite common but it usually doesnt happen within 3 months. mine went after 2 years on a mac pro desktop ($900, thank you applecare took care of it). it has to do with the processor compatibility. sorry for your mpb but it happens to all apples it seems like.
http://discussions.apple.com/thread.jspa?threadID=1995151&start=0&tstart=0