In Virtex-6 FPGA instances of the RXAUI v1.1 core, the MMCM parameter values used in the example design will result in an unsupported multiplication factor of 4. This will result in DRC failures in the next release of the ISE Design Suite software.
For more information on the MMCM issue, see (Xilinx Answer 33849).
The MMCM parameter values should be changed as follows:
CLKFBOUT_MULT_F: from 4.0 to 6.0
CLKOUT0_DIVIDE_F: from 2.0 to 3.0
CLKOUT1_DIVIDE: from 4 to 6