Due to a problem in the Quartus® II software version 12.0 and later, you might see this error during the Fitter if your design targets a Stratix® V FPGA design containing a PLL Intel® FPGA IP with an output clock that is unconnected.
To work around this problem, either connect the phase locked loop (PLL) output clock to your desired logic or remove it from the instantiation of the PLL Intel® FPGA IP.
This problem is fixed starting with the Quartus® II software version 12.1.1.