When XDL is run with the "-ncd2xdl" switch to generate a netlist description of an NCD, the following fatal error message occurs:
"FATAL_ERROR:XDL:Pds2Xdl_PhysicalBlock.c:868:1.33 - Encoding error. Process will terminate. For technical support on this issue, please open a WebCase with this project attached at http://www.xilinx.com/support."
This can occur as a result of XDL being run on a protected design when Synplify is the synthesis tool.
The error message should read "ERROR:XDL - XDL cannot run on a protected design.", preventing XDL from being run on the design.
This issue is currently under investigation to improve the failure mode so that a proper error message is reported.