NGDBuild might generate errors similar to the following:
"FATAL_ERROR:basut:basutptrfil.c:66:1.4 - Pointer already registered..."
"FATAL_ERROR:Utilities:UtilPtrfilimp.c:140:1.5 - Pointer already registered..."
(These two errors derive from different versions of the design tools.)
These error messages are the result of a corrupted ".ngo" file being read into NGDBuild.
The "fe.log" file will show which ".ngo" file was the culprit; delete this file and regenerate it.
It might be sufficient to delete the file and re-run NGDBuild (i.e., the file might have been generated by NGDBuild itself).