subroutine problem

[Gedi]

Hi all,
 
I have recently started to learn perl. After reading Randal Schwartz’s
Learning perl, I decided to give my first program a whirl.
Upon writing it, I was checking each section of code as I went along to
make sure everything worked.
 
I got to one section and couldn’t get it to run as a subroutine. I don’t
fully understand the error I am getting and am hoping somebody can point
me in the right direction.
 
Here is a snippet of my code (edited/reduced to about ¼ of the full
size) which gives the same error as my full program. 
 
#usr/bin/perl -w
 
#use strict;
use warnings;
use IO::Socket;
 
print "1. network Listing only\n";
print "2. Port scan only\n";
 
print "\nPlease enter selection: ";
chomp (my $selection = <STDIN>);
 
if ($selection == 1) {
     #bla bla, don't need this info
}
elsif ($selection == 2) {
     print "\nEnter target: ";
     chomp(my $target = <STDIN>);
     print "Enter start port: ";
     chomp(my $port = <STDIN>);
     print "Enter end port: ";
     chomp(my $end_port = <STDIN>);
     &scan;
}
 
 
sub scan {
     
     print "Scanning $target | from port $port to $end_port\n\n";
     foreach (; $port<=$end_port; $port++) {
           if ( IO::Socket::INET->new(
                PeerAddr   => $target,
                PeerPort   => $port,
                Proto      => 'tcp',
                Timeout         => 1)) {
                print "Port $port is open\n";
           }
     }
     print "\nPort scan complete\n";
     exit;
}
 
 
Can anyone suggest why I am getting an error and how I can fix it?
 
Thanks
 
Ged.