Your steps seem fine, but what is it that you are seeing that doesn’t seem correct?
check to see if you can properly open the web.config file in your browser ? if there is a formatting problem from what you have changed it will cause a problem
also though, do bear in mind that if you add in large movies then this will have a direct impact on the performance of the form for your users as the file will need to be ‘downloaded’ before the form will initiate.
It can be better to upload such large movies to your website and then present a ‘click here’ link on your form so your users can open the movie independently of the form (and of course you can give them a message to say ‘may take a while to download, please be patient’ type of message as well)