Bug with Tsearch and tsvector

PostgreSQL 8.3.10 (on i686-redhat-linux-gnu, compiled by GCC gcc (GCC) 4.1.2 20080704 (Red Hat 4.1.2-46))
OS: Linux Redhat EL 5.4
Database encoding: LATIN9

Using the default tsearch configuration, for 'english', text is being wrongly parsed into the tsvector type.
The fail condition is shown with the following example, using the ts_headline function to highlight the issue.

SELECT ts_headline('english', 'The annual financial report will shortly be posted on the Company’s web-site at
<span lang="EN-GB">http://www.harewoodsolutions.co.uk/press.aspx</span><span lang="EN-GB" style=""></span><span style="">
and a further announcement will be made once the annual financial report is available to be downloaded. </span>',
to_tsquery(''), 'MaxWords=101, MinWords=100');

Output:
"The annual financial report will shortly be posted on the Company&#8217;s web-site at
http://www.harewoodsolutions.co.uk/press.aspx</span><span lang="EN-GB" style="">
and a further announcement will be made once the annual financial report is available to be downloaded. "

Expected output:
"The annual financial report will shortly be posted on the Company&#8217;s web-site at
http://www.harewoodsolutions.co.uk/press.aspx
and a further announcement will be made once the annual financial report is available to be downloaded. "

Regards
Donald Fraser