if ($value_add gt 0){
    foreach $value (@value_add){
    print "Is $value an attribute (y or n)?  ";
    $response = <STDIN>;
    chomp($response);
        if ($response =~ "y" || $response =~ "Y"){
        print "response is $response\n";
        print "configure as an attribute\n";
        }
        else {
            print "response is $response\n";
            print "configure as a parser\n";
        }
    } # end foreach $value (@value_add)
}
[download]

So, unless you declare $value up above this snippet, you aren't using strict, which is foolhardy. You seem to be using a string comparison operator (gt) for a numerical comparison, which doesn't seem the best way to skin this cat.

In any case, the following standalone snippet works fine under perl 5.8.8 on a Solaris platform:

#!/usr/local/bin/perl
use strict;
use warnings;

Main: {
  my @param_names  = ('elevation','location_type','point_name','positi
+on','road_type','road_type_description','vegetation');
  categorize_attributes(\@param_names);
}

sub categorize_attributes {
  my ($value_ref) = @_;
  my @value_add = ();
  @value_add = @{$value_ref} if ref($value_ref) eq 'ARRAY';
  if (scalar(@value_add) > 0){
    foreach my $value (@value_add){
      print "Is $value an attribute (y or n)?  ";
      my $response = <STDIN>;
      chomp($response);
      if ($response =~ /^y$/i){
        print "response is $response\n";
        print "configure as an attribute\n";
      }
      else {
        print "response is $response\n";
        print "configure as a parser\n";
      }
    } # end foreach $value (@value_add)
  }
}
[download]

Update: Modified code sample so that the user input was handled by a subroutine, as specified by the OP.

Update: Oops. Reading from STDIN flushes STDOUT.