Hard to trace then unless you are good at PHP.
Check admin/functions.php after:
PHP Code:
// ###################### Start buildpostbit #######################
$firstnew = 0;
function getpostbit($post) {
It's the function that parses postbit template. I suggest checking the recent hacks applied which made modifications at this file.. You might have applied a date related hack wrong like Today/Yesterday Hack or Blink Date if Message is older than X days hack.