This error message is displayed when opening a Quartus® II v13.1.4 Qsys system in Quartus II v14.0 or later, if the system has an Altera® Avalon®-MM Hard IP for PCI Express® with High or Maximum RX Buffer Credit Allocation chosen.
In addition, when parameterizing the Avalon-MM Hard IP for PCI Express in Quartus II v14.0 or later, the High and Maximum settings for the Rx Buffer Credit Allocation are not available.