Can you share the directory & file structure of your app? (Removing any sensitive information of course)?
The error you're getting indicates that you don't have an "index.html" file in the right place.
Where is the right place
Recommended structure is config.xml file and www folder at the root of your project and index.html and the css/js inside the www folder
Thanks problem was index file was spelt with capital
How do i create app to load with background image