As others have pointed out there are some problems with
your code. But here is a version that seems to work..

use strict;
use warnings;

use Tk;
use Tie::IxHash;

my %hash;
my @w;
my $i=1;

tie %hash, "Tie::IxHash";

%hash =(
1=>["Sappy",
"Jewell",
"2515 E Princeton",
"Visalia",
"CA"
],
2=>["Roomy",
"Hilton",
"12803 Westledge Ln",
"Fifa",
"Transvania"],
3=>[
"Lala",
"Deena",
"423 Northland Street",
"St. Louis",
"Misery"
],
4=>[
"LOLO",
"Homy",
"444 Wold City",
"Foxy",
"Flowerida"
],
);

my @fields = qw/First_Name
Last_Name
Address
City
State
/;


my $mw=MainWindow->new (-title=>"Data Test");
my $rec_no=keys %hash;

my $label = $mw->Label(-text=>"dummy_label");
$label->pack;
my $t=$mw->Scrolled("Text",-width=>50,-wrap=>'none')->pack(-expand=>1,
+-fill=>'both');

for my $index (0..4) {
    $w[$index]=$t->Label(-text=>"$fields[$index]",-relief=>'groove',-w
+idth=>20);
    $t->windowCreate('end',-window=>$w[$index]);
    $w[$index]=$t->Entry(-width=>20,-textvariable=>\$hash{$i}[$index])
+;
    $t->windowCreate('end',-window=>$w[$index]);
    $t->insert('end',"\n");
}

my $next =$mw->Button ( -relief=>'raised', -text=>"Next >>", -state=>'
+normal',-command=>\&next );
my $back =$mw->Button(-relief=>'raised', -text=>"<< Back", -state=>'no
+rmal',-command=>\&back );

&process_rows();

MainLoop;

sub process_rows{
    $next->configure(-text=>"Next", -state=>'normal',-command=>\&next)
+;
    $back->configure(-text=>"Back", -state=>'normal',-command=>\&back)
+;

    $back->configure(-text=>"Back", -state=>'disabled',-command=>\&bac
+k) if $i == 1;
    $next->configure(-text=>"Next", -state=>'disabled',-command=>\&nex
+t) if $i == $rec_no;

    for my $k(0..4){
        $label->configure(-text=>"$i");
        $label->pack;
        $w[$k]->configure(-textvariable=>\$hash{$i}[$k]);
        $t->configure();
        $back->pack(-anchor=>'center', -side=>'left');
        $next->pack(-anchor=>'center', -side=>'right');
    }
}

sub next{
    $i++ unless $i == $rec_no;
    &process_rows();
}

sub back{
    --$i unless $i == 1;
    &process_rows();
}
[download]

There still is room for improvement ;-)
si_lence