centos 7 boot failure XenServer 6

Jul 12, 2014 7:02:47 PM Error: Starting VM 'tank7' - Internal error: xenopsd internal error: VM = dedce812-ee66-3055-ea37-68fde03dcb9a; domid = 414; Bootloader.Bad_error Traceback (most recent call last):
  File "/usr/bin/pygrub", line 903, in ?
    fs = fsimage.open(file, part_offs[0], bootfsoptions)
IOError: [Errno 95] Operation not supported