Try constructing your Worker with a relative path:
If that doesn't work, you need to do some investigation:
If you're using Google Chrome, press Ctrl+Shift+J to open the developer tools.
- Press the Network tab, click the Record button and refresh. Check to make sure setValues.js is loaded.
- Press the Scripts tab, and click 'Debug' beside the Workers item on the right. Then you will be able to place a breakpoint in your Worker.