How do I update a MySQL table each time a page loads?

I am trying to debug some things going on within a particular page on my website.

To do this, i have set up a table in my database called '404'. I would like to write a few values to this table each time the page loads 开发者_StackOverflowbut i'm not having success.

Currently have the following php code at the top of this page:

  <?php include_once $_SERVER['DOCUMENT_ROOT'] . "/incl_func/env_constants.php"; ?>
    <?php
    //check 404 visits
    $ip = $_SERVER['REMOTE_ADDR'];
    $date = date("Y-m-d H:i:s");
    $agent = $_SERVER['HTTP_USER_AGENT'];
    $refer = $_SERVER['HTTP_REFERER'];

    $query = @mysql_query("INSERT INTO 404 (REF_URL, IP, AGENT, DATE) VALUES ('$refer', '$ip', '$agent', '$date')");    
    ?>

I think this issue requires that i do this via ajax but I keep running into walls when trying to get this to work.

Thanks in advance for any help you can provide.

thanks everyone for the help. I was able to solve this by looking at the logs--was a better solution afterall. Turns out the issue with the 404 had to do with yahoo changing its geo locator service today. I wasn't aware they were discontinuing it