maybe the answer here
<<The module is completely useless...>>

update:
i try this code

use Mail::Webmail::Gmail;

    my $gmail = Mail::Webmail::Gmail->new( 
                username => 'poolpi', password => 'passwd',
            );

    my @labels = $gmail->get_labels();

    my $messages = $gmail->get_messages( label => $labels[0] );

    foreach ( @{ $messages } ) {
        if ( $_->{ 'new' } ) {
            print "Subject: " . $_->{ 'subject' } . " / Blurb: " . $_-
+>{ 'blurb' } . "\n";
        }
    }
[download]

login OK but $gmail->get_labels() return -1 !!

PooLpi