Error - export a base_report_creator report

[Ferdinand]

To reporduce
* create a (very simple - one table) report with base_report_creator
* open the report
* Form/Export -> Error

Traceback (most recent call last):
  File "/usr/lib/python2.6/site-packages/Koo/Rpc/Rpc.py", line 151, in call
    result = self.singleCall( obj, method, *args )
  File "/usr/lib/python2.6/site-packages/Koo/Rpc/Rpc.py", line 140, in singleCall
    result = self.proxy.dispatch( obj[1:], method, self.databaseName, self.uid, self.password, *encodedArgs )
  File "/usr/lib64/python2.6/site-packages/Pyro/core.py", line 392, in __call__
    return self.__send(self.__name, args, kwargs)
  File "/usr/lib64/python2.6/site-packages/Pyro/core.py", line 462, in _invokePYRO
    return self.adapter.remoteInvocation(name, Pyro.constants.RIF_VarargsAndKeywords, vargs, kargs)
  File "/usr/lib64/python2.6/site-packages/Pyro/protocol.py", line 429, in remoteInvocation
    return self._remoteInvocation(method, flags, *args)
  File "/usr/lib64/python2.6/site-packages/Pyro/protocol.py", line 454, in _remoteInvocation
    answer = pickle.loads(answer)
  File "parser.pxi", line 23, in lxml.etree.XMLSyntaxError.__init__ (src/lxml/lxml.etree.c:60305)
TypeError: ('__init__() takes exactly 5 positional arguments (2 given)', <class 'lxml.etree.XMLSyntaxError'>, (None,))