A problem has been introduced in ISE version 9.2 that causes PAR to crash (on 64-bit platforms only) if the clock placer (placement phase 4.2) fails to find a solution.
NOTE: This problem does not affect 32-bit platforms.
This problem will be fixed in ISE version 9.2i SP1.
Meanwhile, the failure can be avoided by setting the environment variable that reverts to an earlier version of the algorithm.
Linux and Solaris:
setenv XIL_PAR_USE_OLD_PH2 1
For general information about setting ISE environment variables, see (Xilinx Answer 11630).