Did you place the html file inside your project folder and refer to its location there before uploading?
Your TextFile world class is interesting, I might try that instead.
Also either I'm not understanding what your saying or your not understanding what I'm saying. The html file I'm referring to is a .txt file with html code. I changed the .txt to .html so it opens in a web page and looks the way I designed it to look. It's not a public website and requires no internet to run, just a web browser, so it's an actual file on my computer. It's URL address is C:\ whatever.
Uploaded scenario cannot access files on your local computer. It (the file) needs to be uploaded to a server (or uploaded with your project) and then its URL will be used to address it.
You need to refer to it by the URL it has when it is uploaded. For various reasons this isn't really possible (the file will be inside a jar file, and the browser doesn't know how to look inside a jar file).