Error parsing XML document

/mnt/stor/prosjekt/menota/public_html/meldingar/2009-05-20.page:12: parser error : Entity 'aring' not defined
            <title>R&aring;d for Menota</title>
                           ^
/mnt/stor/prosjekt/menota/public_html/meldingar/2009-05-20.page:44: parser error : Entity 'eth' not defined
aven - og ser fram til den islandske homilieboken i Holm perg 15 4to og Mö&eth;
                                                                               ^
/mnt/stor/prosjekt/menota/public_html/meldingar/2009-05-20.page:54: parser error : Entity 'nbsp' not defined
<p>&nbsp;</p>
         ^
 at /usr/lib/perl5/site_perl/Aksis/XSLTransformer/Application.pm line 154