Description
You may get this error message in the Quartus® II software when the output pins and/or bidirectional pins exceeds the specified number of consecutive pads. This could cause noise on the VREF voltage respective to that bank, which could then cause any inputs depending on that VREF to be read incorrectly.
Resolution
Reassign some of the output pins and/or bidirectional pins out of the specified set of consecutive pads or move all input pins to a different VREF bank.