Thank you for your reply. I played around with it some more and looked at the form information on the page. I realized that there were 2 forms, I amended the code to:
#!/usr/bin/perl
use strict;
use diagnostics;
use warnings;
use WWW::Mechanize::Firefox;
my $mech = WWW::Mechanize::Firefox->new();
print "What word would you like to know the anagrams of?\n";
my $word = <STDIN>;
$word = chomp( $word );
$mech->get( 'http://www.wordsmith.org/anagram/index.html' ) or die "Un
+able to access page.\n";
$mech->form_number(2);
$mech->field( 'anagram', $word );
$mech->submit_form;
wait until $mech->success();
print $mech->content;
Now it has no error messages; however, it seems to be printing the original website, rather than the results of my query.