use strict;     # good
use warnings;     # good
use Net::Whois::IP qw(whoisip_query);
# I can't test as I don't have the Net::Whois::IP
# module installed
use Data::Dumper;
# Here is a module you invoke but from which you don't
# call anything, at least in this example.

&whois();  # why do you call this with no params
           # and use lexicals form the $main::
           # package within it? This is not
           # directly related to your problem, but
           # is bad form. You also call it in void
           # context even though you make it return
           # values...

my ($ip, $email, $techname);
# The above call returns things that are not
# declared until here. Think about what my() will
# do to these variables at this point in the program.

print "$ip\'s name is $techname and email address is $email\n";
# There's a concatenation done here. Is this
# the line that complains? Why would these variables
# not be initialized?

sub whois{

 $ip = '149.1.1.1';

 my ($response,$array_of_responses) = whoisip_query($ip);

 $email = $response->{TechEmail};
 $techname = $response->{TechName};

return ($email, $techname); # Here you return something
                            # which your main program
                            # is throwing away because
                            # the sub is called in
                            # void context.


####!!! There should be a closing curly for this sub!!!

##</code><code>##

use strict;
use warnings;
use Net::Whois::IP qw(whoisip_query);
use Data::Dumper;

my ($ip, $email, $techname);
$ip = '149.1.1.1';

( $email, $techname ) = whois($ip);

print "$ip\'s name is $techname and email address is $email\n";

sub whois {
  my $addr = shift;
  my ($response,$trash) = whoisip_query($addr);

  $email = $response->{TechEmail};
  $techname = $response->{TechName};

  return ($email, $techname);
}