Error parsing XML document

/mnt/stor/prosjekt/menota/public_html/guidelines-2-add/recomm.page:27: parser error : Entity 'aring' not defined
            <language ident="nb">Norsk - Bokm&aring;l</language>
                                                    ^
/mnt/stor/prosjekt/menota/public_html/guidelines-2-add/recomm.page:59: parser error : Entity 'nbsp' not defined
         <p> &nbsp;</p>
                   ^
/mnt/stor/prosjekt/menota/public_html/guidelines-2-add/recomm.page:63: parser error : Entity 'iacute' not defined
<p>We would like to thank Haraldur Bernhardsson (Reykjav&iacute;k) and Andrea de
                                                                ^
/mnt/stor/prosjekt/menota/public_html/guidelines-2-add/recomm.page:64: parser error : Entity 'nbsp' not defined
<p>&nbsp;</p>
         ^
/mnt/stor/prosjekt/menota/public_html/guidelines-2-add/recomm.page:211: parser error : Entity 'thorn' not defined
<p><hi rend="bold">Question</hi>: The word <q>&thorn;az</q> should be analysed a
                                                     ^
/mnt/stor/prosjekt/menota/public_html/guidelines-2-add/recomm.page:211: parser error : Entity 'thorn' not defined
ion</hi>: The word <q>&thorn;az</q> should be analysed as a fusion of <q>&thorn;
                                                                               ^
/mnt/stor/prosjekt/menota/public_html/guidelines-2-add/recomm.page:211: parser error : Entity 'thorn' not defined
 <q>&thorn;az</q> should be analysed as a fusion of <q>&thorn;at es &gt; &thorn;
                                                                               ^
/mnt/stor/prosjekt/menota/public_html/guidelines-2-add/recomm.page:211: parser error : Entity 'thorn' not defined
> should be analysed as a fusion of <q>&thorn;at es &gt; &thorn;ats &gt; &thorn;
                                                                               ^
/mnt/stor/prosjekt/menota/public_html/guidelines-2-add/recomm.page:233: parser error : Entity 'thorn' not defined
and <hi rend="italic">dipl</hi> levels, the word will be displayed as <q>&thorn;
                                                                               ^
/mnt/stor/prosjekt/menota/public_html/guidelines-2-add/recomm.page:233: parser error : Entity 'thorn' not defined
 as <q>&thorn;az</q>, and on the <hi rend="italic">norm</hi> level as <q>&thorn;
                                                                               ^
/mnt/stor/prosjekt/menota/public_html/guidelines-2-add/recomm.page:233: parser error : Entity 'thorn' not defined
<hi rend="italic">norm</hi> level as <q>&thorn;ats</q>. The word form <q>&thorn;
                                                                               ^
/mnt/stor/prosjekt/menota/public_html/guidelines-2-add/recomm.page:233: parser error : Entity 'aacute' not defined
ats</q>. The word form <q>&thorn;az</q> will be linked to the lemma <q>s&aacute;
                                                                               ^
 at /usr/lib/perl5/site_perl/Aksis/XSLTransformer/Application.pm line 154