# Parens, not curlies
my %hash = (this => "one", that => "two"); 
# Use a slash when dumping @var or %var
print Dumper(\%hash);
print($hash{this}, "\n");

##</code><code>##

my $hash = { this => "one", that => "two" }; 
print Dumper($hash);
print($hash->{this}, "\n");