So you want to remove a random element, here's the code that works for me.

$random_file = "test.txt";

open (FILE, $random_file);
@LINES=<FILE>;
close(FILE);
srand;

# Choose a random line
#scalar(@LINES) is the number of elements in the array
$OTP = "$LINES[(int rand(scalar(@LINES)))]";

$PWFILE = $OTP;
open (FILENEW, ">$random_file");
foreach $LINES (@LINES) {
    if ($PWFILE eq $LINES){
    $LINES = ""
    }
  else
  {
      print FILENEW $LINES;
  }
}

close (FILENEW);

# If you want to remove the newline, I don't know much
# about html stuff...it may cause problems?
#chomp( $OTP );

$PPP = $OTP;
[download]

I tested it with a file that looks like this:

test
test1
test2
test3
test4
[download]

It removed a random element from the file, and had it in $PWFILE. I don't know about the rest of the file, but you could probably remove $PPP and $PWFILE and just use $OTP.

I also did not fix the style, I would avoid using all capital var. names except for filehandles.

Hope this helps!