Actually, just seen that you do this:
PHP Code:
$_POST['threadid'] = $vbulletin->db->escape_string($_POST['threadid']);
$_POST['ajax_lastpost'] = $vbulletin->db->escape_string($_POST['ajax_lastpost']);
$_POST['ajax_lastedit'] = $vbulletin->db->escape_string($_POST['ajax_lastedit']);
So you are escaping... just numbers as strings.
Weird though... how did ".:" get into the posted info on some requests?
I had about 20 of those errors over a 5 minute period.