TATTATGAGAATAGTGTGCATTTT	3
ATAGAGCAAAAGGGCAAATGCTGA	6
TACGAGTAGGATATCGATCTGGTGG	2
ATCCCCGGCATCTCCGCCA	1
TGAGAATAGTGTGCATTT	52
CGCATTACATTTGGAGCC	1
ACTCCAGGCAGCGTAGAGTT	1
ATCAACGTTGCTGCATCGG	1

##</code><code>##

>dme0_count=3
TATTATGAGAATAGTGTGCATTTT	
>dme1_count=6
ATAGAGCAAAAGGGCAAATGCTGA	
>dme2_count=52
TGAGAATAGTGTGCATTT	

##</code><code>##

#!/usr/bin/perl -w

use strict;
use warnings;


my $species=$ARGV[0];
my $input=$ARGV[1];
my @fields;
my $n = 0;


open my $tabdata, '<', "$input" or die ("Can't open $input\n"); 

while  (my $line = <$tabdata>)
{
foreach my $line ($tabdata){
	my @fields = split("\t",$line);
	if(($fields[1] > 2) && (length($fields[0]) > 14 && length($fields[0]) < 31))
	
		{print ">$species" . $n++ . "_count=$fields[1]\n$fields[0]\n"};

		}
}
close ($tabdata);


##</code><code>##

Here is the error:
a> line 1.
Use of uninitialized value $fields[1] in numeric gt (>) at tab.pl line 19, <$tabdata> line 2.
Use of uninitialized value $fields[1] in numeric gt (>) at tab.pl line 19, <$tabdata> line 3.
.
.
.
Use of uninitialized value $fields[1] in numeric gt (>) at tab.pl line 19, <$tabdata> line 21.