Strange error....

OK - my group is finalizing a website and we have a convoluted form ... and when we moved it from our server to the end clients we started getting the error:
Warning: Invalid argument supplied for foreach() in /usr/local/www/vhosts/mtrinc.com/htdocs/mirror/inquiry_handler.php on line 112

Here is the relevant code

$section = array();
$labels = array();
$message = array();

foreach ($_POST as $key => $val)
    {
    $section[] = $key;
    foreach ($val as $tit => $dat)
        {
        $labels[] = $tit;
        $message[] = $dat;
        }   
    }


UPDATE:
- It works on the testing server, but not on the live server
- I have verified that there is POST data. Plus, there is a test for POST data at the top.
- all the form cells have names like "something[]" so $ val is always an array.
- have also declared $val, $labels, $message as arrays

I need to find out why this would work on one server and not on the other.

Anyone have any ideas?

SOLVED: turns out a tracking variable added later is not a an array. Sheesh. Thanks for all the help :D