XSLT test error

[Jonny Barnes]

Following installation instructions at
http://intertwingly.net/code/venus/docs/installation.html when
executing runtests.py I get this error:

user at jonnybarnes.net [~/public_html/planet]# python runtests.py
libxml2 is not available => can't test xpath_sifter
Django is not available => can't test django filters
Redland RDF is not available => can't test FOAF reading lists
....Unable to locate filter addsearch.xslt
E............................................................................................................................................................................................................
======================================================================
ERROR: test_addsearch_filter (tests.test_filter_xslt.XsltFilterTests)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/home/user/public_html/planet/tests/test_filter_xslt.py", line
22, in test_addsearch_filter
    self.assertTrue(output.find('<h2>Search</h2>')>=0)
AttributeError: 'NoneType' object has no attribute 'find'

----------------------------------------------------------------------
Ran 209 tests in 5.450s

FAILED (errors=1)

It then says to ask here. Any help much appreciated,

Jonny.