Sorry for the uninteresting post, but I was trying my Altera design in ISE 8.1i and XST crashed immediately with FATAL_ERROR:Xst:Portability/export/Port_main.h:127:1.16 - This application has discovered an exceptional condition from which it cannot recover. Process will terminate etc.
I tried to file a WebSupport case, but I can kind of understand the previous rant thread here as it is a really frustrating experience; I even tried resetting my password, but the login system doesn't give me access (this happens for both firefox and IE).
Xilinx should probably look into this seriously as I'm sure that most would just give up and not report the bugs.
I the meantime, if someone from Xilinx cares about this bug, please contact me directly (tommy-xilinx (at) numba-tu.com).
All the best, Tommy