Mutiple update not working

Been trying for days to get this working, but multiple updates isn't working. I'm setting the update data to the form data submitted (I think), and I have used both methods of creating the multiple update (DataAssist / Update / Multiple Records Update and MySQLi / Data Management / MySQLi Update Multiple Records), but I think they lead to the same wizard.

What am I missing?

Also, when I ran this for the first few times, I got an error which I have screen shot for you. It's attached along with the file containg the multiple update

Just tried again and still not gettting any joy. This time it's a simpler document and it redirects to done.php, but it's not even doing that. So I can only conclude that there is some sort of minimum criteria to be met to submit... but I haven't set any. The only field I'm trying to update is the quantity filed, but it's just not happening. No update to amounts and no redirect on button press.

Another file is attached for you.

You have your trigger set to the quantify field, but that is the dynamic field, so that won't work. Try updating the trigger to use the button press of the submit button you have on the page.