Description
Due to a problem in the Quartus® II software version 13.0SP1 and QII13.0, this error may be generated by Qsys when the hardware multiplication type in Nios® II is set to Embedded Multipliers (eg. In Cyclone® III device) and then the Nios II core is switched to Nios II/e core (eg: switch to Stratix® IV device)
Resolution
To workaround this problem in the Nios II Megawizard GUI, set the Multiplier type to None before switching the NiosII core type to NiosII /e core.
This problem is scheduled to be fixed in a future release of the Quartus II Software.