First the code in question (just a test case):
// This page is receive.php
<form action="receive.php" method="post">
<input id="message" type="text" size="16" />
<button type="submit">Submit</button>
</form>
<br /><br />
<?php
if(!$_POST == NULL) {
echo ($_POST['message']);
}
?>
I've been having quite a bit of trouble with information being sent via form not ending up in the $_POST array. I tried simplifying the script as much as possible, thinking something else in the code was messing it up, but the above is about as barebones as I can make it and still doesn't work.
I'm running Apache 2.0.55 with PHP 5.1.2 on Windows XP Home SP2. It may be worthy of note that before upgrading Apache and PHP a few days ago (from 2.0.48 and 5.1.0 respectively), this problem didn't occur.