I slightly modified your code, as follows:

use strict;
use Time::Local;
use warnings;
 
my $counter = 0;
my($address) = @_;
my $str;
my $flag=0;
my $file = 'C:\ListOfIpAdress.txt';
open my $fho, '>', 'ListOfIpAdress2.txt' or die "Could not open file $
+!";
while (my $line = <DATA>) 
{   
     my ($a1, $a2, $a3, $Day, $sMonth, $sDate, $sTime, $SYear,$a9, $a1
+0) = split(/ {1,}/, $line);
     my $str1=  $sMonth." ".$sDate." ".$sTime ;
     my $scTime = localtime;   
     my ( $cDay, $cMonth, $cDate, $cTime, $cYear,$Syear) = split(/ {1,
+}/, $scTime);    
     my  $str2=  $cMonth." ".$cDate." ".$cTime ;
     use constant Year => 2015;
     my $t1 = convert($str1);
     my $t2 = convert($str2);
     my $Diff= $t2 - $t1;
     my $div = $Diff/3600;
     print "Total Difference in Hour is : $div \n\n";
     print $fho $line unless $div > 38;
}
print "\nn check1 \n\n"; 
close $fho;
print "\nn check2 \n\n";
unlink ($file);
if(-e $file) 
{
   print "File still exists!";
}
else 
{    
   print "File gone.";
}

 sub convert
{
    my $dstring = shift;

    my %m = ( 'Jan' => 0, 'Feb' => 1, 'Mar' => 2, 'Apr' => 3,
            'May' => 4, 'Jun' => 5, 'Jul' => 6, 'Aug' => 7,
            'Sep' => 8, 'Oct' => 9, 'Nov' => 10, 'Dec' => 11 );

    if ($dstring =~ /(\S+)\s+(\d+)\s+(\d{2}):(\d{2}):(\d{2})/)
    {
        my ($month, $day, $h, $m, $s) = ($1, $2, $3, $4, $5);
        my $mnumber = $m{$month}; # production code should handle erro
+rs here

        timelocal( $s, $m, $h, $day, $mnumber, 1900 );
    }
    else
    {
        die "Format not recognized: ", $dstring, "\n";
    }
}
__DATA__
Address: 100.64.52.98 Time Fri Jan 16 21:44:35 2015 End
Address: 100.65.0.172 Time Fri Jan 16 21:46:48 2015 End
Address: 100.64.58.219 Time Fri Jan 16 22:56:16 2015 End
Address: 100.65.5.25  Time Fri Jan 16 23:10:04 2015 End
Address: 100.64.8.184 Time Fri Jan 16 23:52:54 2015 End
Address: 100.65.13.135 Time Fri Jan 16 23:59:46 2015 End
[download]

and I do get the following output:

$ perl logs.pl
Total Difference in Hour is : 37.5744444444444

Total Difference in Hour is : 37.5375

Total Difference in Hour is : 36.3797222222222

Total Difference in Hour is : 36.1497222222222

Total Difference in Hour is : 35.4358333333333

Total Difference in Hour is : 35.3213888888889


n check1


n check2

File gone.
[download]

And the ListOfIpAdress2.txt is duly created:

$ cat ListOfIpAdress2.txt
Address: 100.64.52.98 Time Fri Jan 16 21:44:35 2015 End
Address: 100.65.0.172 Time Fri Jan 16 21:46:48 2015 End
Address: 100.64.58.219 Time Fri Jan 16 22:56:16 2015 End
Address: 100.65.5.25  Time Fri Jan 16 23:10:04 2015 End
Address: 100.64.8.184 Time Fri Jan 16 23:52:54 2015 End
Address: 100.65.13.135 Time Fri Jan 16 23:59:46 2015 End
[download]

I do not know if this the result you are looking for, but I don't get the error you are reporting.

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