There is no longer a patch required for Virtex-6 or Spartan-6 FPGA. All issues which were addressed in the patch for ISE 11.2 are resolved in the ISE 11.3 software installation. Many other improvements and fixes are also included for Virtex-6 and Spartan-6 FPGA, so it is highly recommended to re-implement your 11.2 design in ISE 11.3 or later software version.
Important Update: There is a known issue with the Spartan-6 FPGA patch that causes EDK to return a Fatal Error when opening a Spartan-6 FPGA project.For more information and the solution, see
(Xilinx Answer 33505).