Thumbnails are not showing in Rating form

Hi Joise,
We are now trying out online judging. I set up EWZ Rating on my staging site. I created my first test scheme and rating form. There are a few problems that I need help with.
1) The folder ewzr_test_images is not in the WordPress Upload folder. I know I can use my own test image, but still the question is why the said folder is not there. Something is amissed.
2) The EWZ created role “EntryWizard Judge” cannot be found in the WP Users. Where else I can find this role so I can assign it to existing users? Which plugin you recommend for assigning dual wp roles?
3) Since I could not assign user to “EntryWizard Judge”, I viewed the rating form as admin. The rating form did not show the image thumbnails. The column title was there and I could see all title names just not the thumbnails.
4) In the rating form, the “Go to next item after setting” drop down is empty. Not sure if this is right or not.
5) There is a php error message: Undefined index: QUERY_STRING. The location identified is wp-content/plugins/ewz-rating/includes/ewz-rating-shortcode.php:285
How do I correct that?

Thanks for your in advance.