You may see this error during Analysis & Elaboration in the Quartus® II software version 7.2 or later, if your project uses a Quartus II Exported Partition (.qxp) file generated by a Quartus II software version prior to 7.2 as a source file.
To avoid this problem, do not include older-format .qxp files as source files in your Quartus II project. Instead, after Analysis & Elaboration, import the .qxp file into your design using the Import Design Partition utility available from the Project menu in the Quartus II GUI.
This problem is scheduled to be fixed in a future version of the Quartus II software.