Hi Dan,
I would say that the error is most likely caused by a hardware error in memory or CPU (more likely memory). The system is detecting an incorrect parity on some block of data and is preventing startup so as to protect from in-memory data corruption. As to what you should do, if you have any service or warranty contracts on the system, contact support. If not, you will either need to procure one (if this is a production critical system I would highly recommend it), or diagnose the system the same way you would a server, pull one stick of memory out, see if it will boot, etc etc.
If anyone else has a better suggestion please chime in
Best Regards,
Adam S.