Replace two Tcl files in the local Quartus® Prime version 15.1.2 or 16.0 installation directory. Use the Quartus zip file corresponding to your Quartus Prime installation. Copy the files to your Quartus Prime installation directory.
1) Copy altera_pcie_a10_hip_fileset.tcl to <install_directory>\ip\altera\altera_pcie\altera_pcie_a10_hip\
2) Copy a10-pcie-devkit-prj.tcl to <install_directory>\ip\altera\altera_pcie\altera_pcie_a10_ed\example_design\
This problem will be fixed in a future Quartus Prime release.