Bitfile generation for the design with Virtex-7 FPGA Gen3 Integrated Block for PCI Express v1.1 core is not supported without locking down system reset.
Users who want to create a bitfile are first required to lock down the system reset to a pin. If you are targeting a Xilinx Development Board, the default IP output locks down the system reset accordingly and bitfile generation is supported in this configuration.
To get rid of the error message, when generating a bitfile for non Xilinx Development Board and without locking down the system reset, add "-ise" to the bitgen options.
05/08/2012 - Initial release