ERROR:Portability:3 - This Xilinx application has run out of memory or has encountered a memory conflict. Current memory usage is 2085100 kb. You can try increasing your system's physical or virtual memory. If you are using a Win32 system, you can increase your application memory from 2GB to 3GB using the /3G switch in your boot.ini file. For more information on this, please refer to Xilinx Answer Record #14932. For technical support on this issue, you can open a WebCase with this project attached at http://www.xilinx.com/support.
This issue will be resolved in ISE software 12.2.
A patch is available for ISE softwaRe 12.1 here: