displaying a local index.html file with webview

hi, i added a file to sketch and the file is located in sketchname/data/index.html, my problem is how do i point to that file using webview.loadUrl("file:///sketch/data/index.html");

it just returns "webpage not available message" so it can't see the file , could this possible be a permissions error? idk

Thanks for any help in advance.