eh I get this

controller.php:
function action_submit_form() {
...
if($qsID==0)
throw new Exception(t("Oops, something is wrong with the form you posted (it doesn't have a question set id)."));

1) after a form submit, the qID not set(reading from the db for the set of questions and not responding fast enough from server)

2) another one:
When you create a form and create some required fields and partially fill it out and click the submit button, so that message "Complete required fields" comes out. If you now try to highlight the web browser url and "press enter to reload" in Safari(it will ignore the #anchor tag and process page) you get this error message:

"Fatal error: Uncaught exception 'Exception' with message 'Oops, something is wrong with the form you posted (it doesn't have a question set id)."

e.g. url is "www.site.com/index.php?cID=1&bID=873&arHandle&ccm_token=1370910640:5908dda131d4cb888d3034eb3258095d&btask=passthru&method=submit_form#1364271682"

- If you remove the #1364271682 and press enter(it will process the page) and you get same error message in FF,IE,Chrome

concrete/blocks/form/controller.php:
$txt = Loader::helper('text');
$db = Loader::db();

if (!isset($_POST['qsID'])) {return;} //fix 2)

//question set id
$qsID=intval($_POST['qsID']);
if($qsID==0)
throw new Exception(t("Oops, something is wrong with the form you posted (it doesn't have a question set id)."));