error detection crc

Hi ,

For SEU mitigation in Stratix iv GX device, I enabled ''Enable error detection CRC" from Device and Pin Options in Quartus II 13.1. But while synthesis got

the error message that " Error(21216): Cannot enable error detection cyclic redundancy check without instantiating the ALTERA_CRCERROR_VERIFY

megafunction ". After instantiating the IP also getting the same error message while synthesis.

Any leads would be appreciated , links to documentation about the megafunction will also be helpful.

Thanks