PHP - Fwrite Wont Make A New File If It Has A Question Mark In It?

So I really don't think I need to paste the code but

Code: [Select]
<?php
session_start();
?>
<?php
$new_thread_page_path = 'general_discussion_threads/' . $_POST['thread_title'] . '.php';
$new_table_link = '<a href="' . $new_thread_page_path . '"' . 'class="hover" border="0" style="text-decoration:none">' . $_POST['thread_title'] . '</a>';
?>
<?php
date_default_timezone_set('EST');
$date = date("m/d/y");
$hour = date("g");
$minute = date("i");
$second = date("s");
$am_pm = date("a");
$full_date = $date . '  ' . $hour . ":" . $minute . ":" . $second . $am_pm;
$place_holder = '<!--the_place_holder-->';
$current_page_path = 'general_discussion_home.php';
$open_current_page = fopen($current_page_path, 'rb');
$contents_of_current_page = fread($open_current_page, filesize($current_page_path));
$template_path = 'general_discussion_threads/template.php';
$open_template = fopen($template_path, 'rb');
$template_contents = fread($open_template, filesize($template_path)); 
$new_thread_page_path = 'general_discussion_threads/' . $_POST['thread_title'] . '.php';
$list_file_path = 'general_discussion_threads/thread_list.txt';
$list_open = fopen($list_file_path, 'rb');
$list_open_write = fopen($list_file_path, 'a');
$open_new_thread_page = fopen($new_thread_page_path, 'w+');
$list_contents = fread($list_open, filesize($list_file_path));
$thread_exists_test = substr_count($list_contents, '<' . strtolower($_POST['thread_title'] . '>'));
$invalid_character_test = substr_count($_POST['thread_title'], '<');
$invalid_character_test1 = substr_count($_POST['thread_title'], '>');
$the_users_info = $_SESSION['the_user'];
$the_username1 = strstr($_SESSION['the_user'], '.');
$the_username1_wipe = str_replace($the_username1, '', $the_users_info);
$the_username = str_replace('.', '', $the_username1_wipe);
if (isset($_POST['new_thread_post'])) {
if (($_SESSION['logged_in'] == '1') && ($invalid_character_test1 == '0') && ($invalid_character_test == '0') && ($thread_exists_test == '0') && ($_POST['thread_title'] != '') && ($_POST['thread_title'] != 'Enter the title of your Thread...')) {
fwrite($open_new_thread_page, '<?php $the_thread_title = ' . '\'' . $_POST['thread_title'] . '\'' . '; ?>' . $template_contents);
fclose($open_new_thread_page);
fwrite($list_open_write, '<' . strtolower($_POST['thread_title']) . '>');
fclose($list_open_write);
$new_contents =str_replace($place_holder, '<tr><td align="center">' . $new_table_link . '</td>' . '<td align="center">' . '<font color="#66CC00">' . $full_date . '</font>' . '</td>' . '<td align="center">' . '<font color="#66CC00">' . $the_username . '<font>' . '</td>' . '</tr>' . $place_holder, $contents_of_current_page);
$open_current_page = fopen($current_page_path, 'w');
fwrite($open_current_page, $new_contents);
fclose($open_current_page);
$_SESSION['gd_error'] = 'Thread created succesfully!';
} elseif ($_SESSION['logged_in'] != '1') {
$_SESSION['gd_error'] = 'You need to be logged in!';
} elseif ($invalid_character_test != '0') {
$_SESSION['gd_error'] = 'Thread title contains invalid characters!';
} elseif ($invalid_character_test1 != '0') {
$_SESSION['gd_error'] = 'Thread title contains invalid characters!';
} elseif ($thread_exists_test != '0') {
$_SESSION['gd_error'] = 'Thread title unavailable!';
} elseif ($_POST['thread_title'] == '') {
$_SESSION['gd_error'] = 'You must make a thread title!';
} elseif ($_POST['thread_title'] == 'Enter the title of your Thread...') {
$_SESSION['gd_error'] = 'You must make a thread title!';
}
}
?>


So what all this does is based on user input it creates a new html page based off of the template with a few different variables based on input. Then it makes a new row  and 3 cells in the home pages thread table that link to the page say who made it and what time they made it. Now it all works PERFECT (Im suprised how perfect on the first try actually) except for 1 tiny flaw which i think might be php not me but im not sure. The fwrite creates a new file but if the input contains any question marks (?) the link will work but no file will be created. For everyother character on teh standard keyboard its fine but not the question mark. What gives? thanks yall!

MOD EDIT: <code></code> tags changed to proper [code] . . . [/code] BBCode tags.