My first instinct is to say it’s not finding your generated script file. I know you have mentioned that if you change the URL it creates an error with a 404. Basically, the code that says you need to “copy” to your document is a DIV plus the script. The Div has an ID that the script uses to place your Hype document. Therefore, at the moment, you are creating a 600x400 px div which has no content when you have the space in the filename. If you put the URL to its correct setting then it throws the 404 error. I’m looking at your first screenshot and the error that says "Cannot read property “blah blah” of null. This means the particle.js file creates an error because I’m assuming it’s looking for elements with a class name and it cannot find them (null)
Using MAMP the default is to serve MAMP on localhost:8888 (i think from memory). Have you changed the default settings?