Asus p5n-e running RAID5 errors

I built a basic server at work using an asus p5n-e running raid5 on the motherboard hardware. i'm using 3 WD 150 gig raptors.

in my logfiles i'm showing that nvraid has failed to read/write. then server is locking up while others are trying to read/write to the server.

would this be a hard drive failure somewhere, or would it be a motherboard failure? the error i'm getting is saying there's a problem w/ Sata 2.0 port.

any ideas or suggestions? i went ahead and ordered two more hard drives and an extra motherboard just in case (even though i had to get a p5n-t because the -e is no longer available)

Thanks in advance for your help.