Try this:

#! perl -slw
use strict;
use List::Util qw[ reduce ];
use Data::Dumper;

my %data;

while( <DATA> ) {
    my( $genre, $title, $fname, $lname ) = split '/';
    $data{ $genre } = {} unless exists $data{ $genre };
    $data{ $genre }{ $title } = [] unless exists $data{ $genre }{ $tit
+le };
    push @{ $data{ $genre }{ $title } }, { fname => $fname, lname => $
+lname };
};

print Dumper \%data;

__DATA__
sitcom/simpsons/homer/simpson
sitcom/simpsons/ned/flanders
sitcom/flintstones/fred/flintstone
sitcom/flintstones/wilma/flintstone
sitcom/flintstones/barney/rubble
gameshow/price is right/bob/barker
gameshow/jeopardy/alex/trebek
[download]