there is a problem in
CT_CoreProperties._set_element_text (line 299)

value = str(value)

which will will fail in a default windows-python2.x installation when supplying unicode strings (e.g.):

UnicodeEncodeError: 'ascii' codec can't encode character u'\xfc' in position 0: ordinal not in range(128)

This is because there is no default system encoding, so python tries to encode the unicode-string using 7-bit-ASCII, which of course fails.

My solution: Only convert to string, if its necessary. If it's already a string/unicode, don't touch.

if not isinstance(value, basestring):
    value = str(value)