Thanks for reply, roboticus!

I forgot to report module version and error message.

>perl twigtest1.pl

not well-formed (invalid token) at line 2, column 8, byte 34 at C:/stra
rl/vendor/lib/XML/Parser.pm line 187.
 at twigtest1.pl line 6.

>perl -MXML::Twig -e "print $XML::Twig::VERSION;"
3.44
>perl -MHTML::TreeBuilder -e "print $HTML::TreeBuilder::VERSION;"
5.03

I got same error with your test data.
This is very strange for me, cause I used XML::Twig as HTML parser for several times, and I got no such error like this. I can't think that there was no "character entity references" at that time...

I would like to try available older version of modules.
regards.