The code you posted doesn't have 17 lines, so the code is likely not responsible for the error messages you posted.

You are reading in a file but you aren't stripping the newlines off the lines read in. Hence $url will have a newline at the end. It is possible but unlikely that your files have names with a newline at the end, so you better strip the newlines after reading the files:

chomp @file;
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As a general tip, never just print out a variable for debugging - always print it out enclosed in some delimiters so you can easily spot leading or trailing whitespace:

print "Url is '$url'\n";
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Taking that tip further, you might want to get in the habit of using one of the data structure serialization modules (Data::Dumper, YAML::Syck) to print out values in debug messages. That way you don't have to go back and add more debugging scaffolding when you have to start tracking down what exactly ARRAY(0xdeadbeef) contains.

use strict;
use warnings;

# File containing review definitions
my $DATA_FILE = 'ReviewUpdatesMarch2007';

# Names of fields in data file
my @DATA_FIELDS = qw( owner new_date url ); 

# Validation routines for each field;
my %VALIDATE_FIELDS; 

{ # Limit scope of disabled warnings;  

  no warnings 'uninitialized';
  %VALIDATE_FIELDS = (

    # owner must be one or more word characters plus whitespace
    owner => sub {
      my $owner = shift;

      return $owner =~ /^[\w\s]+$/;
    },

    # new_date must be 6 digits broken into pairs by  slashes or dashe
+s
    new_date => sub {
      my $date = shift;

      return $date =~ /^\d\d[\/-]\d\d[\/-]\d\d$/;
    },


    # url must be all word characters or :/&?+#
    url => sub {
      my $url = shift;

      return $url =~ /^[\w:\/&?+#]+$/;
    },  
    # this is not really a good way to use to validate urls.
    # there is probably a cpan module that will do so correctly.
    # but I am too lazy to find it for you.

  );

}


my @reviews;  # Review data as hash references

# Uncomment this to pull data from file
#open ( FILE, '<', $DATA_FILE )
#  or die "Error opening data file $DATA_FILE - $!";

# Parse lines and store in @reviews
ITEM:
# Uncomment this to pull data from file
#while ( defined my $item = <FILE> )
while ( defined( my $item = <DATA> ) ) # Delete this to pull data from
+ file
{
  chomp $item;  # Failing to chomp your input may have been the cause 
+of your error

  my %item;
  @item{ @DATA_FIELDS } = split( /\t/, $item );

  foreach my $field ( @DATA_FIELDS ) {

    unless( 
      $VALIDATE_FIELDS{$field}->( $item{$field} )
    ) 
    {
      warn "Invalid data in field '$field' from line '$item'\n";

      # Skip bad data
      next ITEM; 
    } 

  }

  push @reviews, \%item;
}

# Uncomment this to pull data from file
#close FILE
#  or die "Error closing $DATA_FILE - $!\n";

# Uncomment to dump your data table for debugging purposes.
#use Data::Dumper;
#print Dumper \@reviews;

foreach my $review ( @reviews ) {
  my $url = $review->{url};

  print "$url\n";
  my $slurp = read_file( $url );

}

sub read_file {
  # do stuff here
  # this is probably where your error is.
}

__DATA__
Good Owner    12/12/23    good_url
Bad!!!Owner    22/22/22    good_url
Good Owner2    BAD DATE    good_url
Good Owner3    12/12/23    bad url

Good Owner4    12/12/23    good_url
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