you must indicate which method will be used to parse the received content.
see HTML::Robot::Scrapper::Parser::Default
To install HTML::Robot::Scrapper, copy and paste the appropriate command in to your terminal.
cpanm
cpanm HTML::Robot::Scrapper
CPAN shell
perl -MCPAN -e shell install HTML::Robot::Scrapper
For more information on module installation, please visit the detailed CPAN module installation guide.