@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
[download]

split divides the string by the character to be split on and returns that many elements to the array. Thus resulting in an array of size 3 for each split per line.

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

Use eq for comparing strings instead of ==