"FATAL_ERROR:NgdBuild:Portability/export/Port_Main.h:116:1.24 - This application has discovered an exceptional condition from which it cannot recover. Process will terminate. To resolve this error, please consult the Answers Database and other online resources at http://support.xilinx.com"
"ERROR:NgdBuild:276 - edif2ngd exited with errors (return code 1)."
"ERROR:NgdBuild:28 - Top-level input design file "top.edf" cannot be found or created. Please make sure the source file exists and is of a recognized netlist format (e.g., ngo, edif, edn, edf or xnf)."
This problem can occur when TNM properties are placed on two different EDIF nets that are connected through the hierarchy into the same signal.