In CVS head, file 'po4a/lib/Locale/Po4a/Xml.pm': if (defined $self->{options}{'doctype'} ) { my $doctype = $self->{options}{'doctype'}; if ( $tag[0] !~ /\Q$doctype\E/i ) { die wrap_ref_mod($tag[1], "po4a::xml", dgettext("po4a", "Bad document type. '%s' expected."), $doctype); } } file 'po4a/lib/Locale/Po4a/Docbook.pm': $self->{options}{'doctype'}=$self->{options}{'doctype'} || 'docbook xml'; So the following valid 'DOCTYPE' be considered invalid ! <!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"> <!DOCTYPE article SYSTEM "http://docbook.org/xml/4.5/docbookx.dtd"> <!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"> <!DOCTYPE article SYSTEM "http://docbook.org/xml/4.5/docbookx.dtd"> --- Dongsheng Song