@lineData = split(/\,/, $line); 

should be...

@lineData = split(/\//, $line); #parse 12/Mar/2004

the above results in:
$lineData[0] = 12
$lineData[1] = Mar
$lineData[2] = 2004

This is causing your comparison:

if($lineData[18] == $date) to be wrong

##</code><code>##

my $line_date = "$lineData[0]/$lineData[1]/$lineData[2]";
if($line_date eq $date){
  print "equal\n";
}