Hey - couple issues with this:
1. If returning false in your onStart, it will exit the script. You couldn't run this from the login screen, as it would immediately exit.
2. walking is a boolean. You don't need to do walking == false, you can just do !walking
3. You never want to return -1, as that's the time between loops. You'd just be wasting resources by running nothing as fast as possible.
4. You never exit the script once it arrives.