Rail analysis (Encounter 9.11)

Hello, I'm trying to do rail analysis in Encounter 9.11 with EPS XL. Early rail analysis works fine, but sign-off level analysis doesn't work. Following is the part of a log file. What could be the source of this problem? Running RC extraction for net vdd ... Invoking: "zx -vstorm -cmd ./work/zx_vdd.cmd" ... INFO (EXTZX-101) : Fire & Ice ZX - RC Extractor - Version v09.11-s023_1 (03/04/2010 05:17:35) ------------------------------------------------------------------------------ Copyright 2007 Cadence Design Systems, Inc. INFO (EXTZX-126) : Command line: /tools/linsoft2/cadence/edi91hf05/tools.lnx86/anls/bin/32bit/zx -vstorm -cmd ./work/zx_vdd.cmd INFO (EXTZX-102) : Starting at 2010-Dec-01 16:51:33 (2010-Dec-01 21:51:33 GMT). INFO (EXTZX-175) : [Input] User enables maximum via clustering mode option. The program uses aggressive via clustering approch to cluster the vias. This approach does not use the "cluster distance" parameters used by the default via clustering approach. INFO (EXTZX-137) : Starting front end processing INFO (EXTNXT-158) : Set layer mapping from cell lib and command file. INFO (EXTZCORE-102) : Loading DEF file /home/gtcad2/mjung7/temp/eps_out_23068.def.gz. Initializing DEF5.6 parser ---------------------- FATAL ---------------------- Exiting due to an internal error. Received signal #11. Contact Cadence customer support at support@cadence.com or call 1-877-CDS-4911. You can also reach Cadence on the web at http://support.cadence.com. ------------------------------------------------------- Ending at 2010-Dec-01 16:51:34 (2010-Dec-01 21:51:34 GMT). Executed by: mjung7 Execution host: gtcad-srv2.ece.gatech.edu Run duration: 00:00:01 CPU time, 00:00:01 clock time Memory used: 130,924,544 bytes Repaired vias used: 0 Unconnected pins: 0 Warning messages: 0 Error messages: 0 Fatal error messages: 1 Exit code 3. Fire & Ice ZX exited unsuccessfully. *** Error: In file /home/gtcad2/mjung7/temp/vstorm_23068.cmd at line number 30 :- R extraction failed.