Your code could definitely benefit from use strict; and use warnings; — you're declaring a hash (and also creating it at the same time), and then you try and treat it like an array when CGI.pm actually expects a hash reference (you can do magic to make something like this work, but you don't want to).

Something like this does what you mean:

use warnings;
use strict;
use CGI qw(:standard);
use Data::Dumper;

my %labels = (
        monkey => "sigmund",
        cat    => "felix",
        dog    => "fido",
);
print radio_group(-name=>'clearchannel',
        -values=>[keys %labels],
        -labels=>\%labels);
[download]

Here I'm creating a hash (the my %labels lines). Pass the list of possible values for the group (monkey; cat; dog) as an array reference created by the [] operator (keys merely returns the keys of a hash as a list). Then provide the labels for each of the values by passing a hashref.