That NaN% error is appearing in the widget because the profile you are using does not have permission to view the Fundraising Goal field on the TeamRaiser Registration record. You can fix this by following these steps: 
  1. Go to Setup > Administration Setup > Manage Users > Profile > click on profile of user. 
  2. Under Field Level Security, find TeamRaiser Registration and click View. 
  3. Click Edit. 
  4. Check the Visible box next to Fundraising Goal. 
  5. Click Save.