The file you're trying to serve seems to be outside your Wordpress installation which is making Wordpress throw a 404 not found.
I suggest placing the files in your wp-uploads folder using Wordpress or an FTP program
for example if your files are here
then you would update the src= attribute to include the absolute url
Then you can place your div code (again with the absolute url!!) into your post/page or into the template you are using, single-page.php, index.php, page.php, etc.
Daniel explains this above but I have made it more personal using your urls
I hope this helps
If you need more clarification let me know