The WebPACK version does not seem to contain the following directory:
C:\Xilinx\14.4\ISE_DS\PlanAhead\data\parts\xilinx\virtex7
Even if you are using a WebPACK tool that supports Kintex-7 or Artix-7 devices, when generating a bitstream in the Vivado Design Suite, certain files are used from the virtex7 directory. However, these are not present with the WebPACK installation, which results in errors.
This issue can be resolved by downloading and applying the following patch:
http://www.xilinx.com/txpatches/pub/swhelp/ise14_updates/ar53703_cr693572_Install_2012_4_preliminary.zip After downloading the ZIP file, please view the readme file for further instructions on how to install the patch