The xps_can_v1_00_a is supported in the Virtex-4 devices and the .mpd file is in error in not listing it.
To correct this issue, please include the Virtex-4 architecture support in the ".mpd" file located at:
%Xilinx\10.1\EDK\hw\XilinxProcessorIPLib\pcores\xps_can_v1_00_a\data
Open the "xps_can_v2_1_0.mpd" file and add the following items in the "OPTION ARCH_SUPPORT_MAP" line 29.
OPTION ARCH_SUPPORT_MAP = (virtex4lx=PREFERRED, virtex4sx=PREFERRED, virtex4fx=PREFERRED, . .....)
The issue will be fixed in the EDK 10.1 Service Pack 3. It will be available at: