[Plugin: WP Super Cache] – Ajax – Wrong content loaded

I’m using an Ajax/jQuery call to load in the sidebar asynch content.
Since I have enabled mod_rewrite, I get old & wrong content.
What can I try?

This the code that triggers jQuery call. Asynch load topposts.php into the foo DIV:

<script type="text/javascript">
    /* this code loads asynchronously content into the div "foo" container*/
            jQuery.noConflict();
             jQuery("#foo").load("/wp-content/themes/tgv1/topposts.php", "",
                function(responseText, textStatus, XMLHttpRequest) {
                    if(textStatus == 'error') {
                        jQuery('#foo').html('There was an error making the AJAX request');
                    }});
    </script>

topposts.php :

<?php
require_once($_SERVER["DOCUMENT_ROOT"]. '/wp-load.php' );
session_start();?>
....... more code here....
?>

Could Wp Supercahce suffer when accessing session variables? Or Ajax calls can scramble WP SuperCache?