On our website, sometimes $\_POST is relayed empty to the action pages.

This happens for roughly about %1-2 of the forms submitted on a daily basis. This is about 50-100 corrupt form submissions per day currently.

We are certain the data is there on the initial page. We tried sending the same data with $\_POST and $\_GET at the same time with the exact same values. $\_GET reaches the action page all the time, but $\_POST can arrive empty.

Often times, this error happens to Webkit besed browsers. Also mobile phone browser seem to be more prone to this. 
IE browsers experience this less than the Webkit browsers.
And very rarely it happens to Firefox as well.

Current configuration is like this:  

**PHP Version 5.2.15  

Centos 5  

Apache 2.2.3**

One thing we are discussing is to upgrade our PHP to 5.3.x.
Does that sound like a reasonable try?

Any suggestions on how we can try to debug this?

**UPDATE:**
Submission form is as follows:

```
<form action="submit.php?receiver_user_id=<?php echo $_SESSION['receiver_user_id'];?>&sender_user_id=<?php echo $_SESSION['user_id']; ?>" method="post">
  <textarea name="message_text" ></textarea>
  <input type="hidden" name="receiver_user_id" value="<?php echo $_SESSION['receiver_user_id'];?>
  <input type="hidden" name="sender_user_id" value="<?php echo $_SESSION['user_id']; ?>
  <input type="image" name="submit" src="submit.png" value="submit"/>
</form>

```