Converting chm to pdf generates a 0 bytes output

Binary package hint: calibre

I just installed calibre in kubuntu 10.10.
calibre:
  Installed: 0.7.18+dfsg-1
  Candidate: 0.7.18+dfsg-1
  Version table:
 *** 0.7.18+dfsg-1 0
        500 http://de.archive.ubuntu.com/ubuntu/ maverick/universe amd64 Packages
        100 /var/lib/dpkg/status

 I am trying to export a chm to a pdf, when I check the log I get the following output:

Combining individual PDF parts...
Traceback (most recent call last):
  File "/usr/lib/calibre/calibre/ebooks/pdf/writer.py", line 177, in _render_html
    self._render_book()
  File "/usr/lib/calibre/calibre/ebooks/pdf/writer.py", line 145, in _render_book
    self._write()
  File "/usr/lib/calibre/calibre/ebooks/pdf/writer.py", line 206, in _write
    outPDF = PdfFileWriter(title=self.metadata.title, author=self.metadata.author)
TypeError: __init__() got an unexpected keyword argument 'title'
PDF output written to /tmp/calibre_0.7.18_tmp_bQqyLA/calibre_0.7.18_aEFyyy.pdf

I've tried exporting to epub format and it works as expected.