raise TypeError, "cannot marshal None unless allow_none is enabled" in cobbler

[root@system kickstarts]# cobbler profile getks RHEL55_64--x86_64
Traceback (most recent call last):
  File "/usr/bin/cobbler", line 35, in ?
    sys.exit(app.main())
  File "/usr/lib/python2.4/site-packages/cobbler/cli.py", line 509, in main
    rc = cli.run(sys.argv)
  File "/usr/lib/python2.4/site-packages/cobbler/cli.py", line 195, in run
    self.object_command(object_type, object_action)
  File "/usr/lib/python2.4/site-packages/cobbler/cli.py", line 266, in object_command
    data = self.remote.generate_kickstart(options.name,"")
  File "/usr/lib/python2.4/xmlrpclib.py", line 1096, in __call__
    return self.__send(self.__name, args)
  File "/usr/lib/python2.4/xmlrpclib.py", line 1377, in __request
    allow_none=self.__allow_none)
  File "/usr/lib/python2.4/xmlrpclib.py", line 1029, in dumps
    data = m.dumps(params)
  File "/usr/lib/python2.4/xmlrpclib.py", line 603, in dumps
    dump(v, write)
  File "/usr/lib/python2.4/xmlrpclib.py", line 615, in __dump
    f(self, value, write)
  File "/usr/lib/python2.4/xmlrpclib.py", line 619, in dump_nil
    raise TypeError, "cannot marshal None unless allow_none is enabled"
TypeError: cannot marshal None unless allow_none is enabled