some questions...
1 - Your CD have a background full transparent?
2 - when you place icons over CD ( drag-n-drop ), do you move it to the center or to the background?
3 - Have you visited
http://circledock.wikidot.com ? read more about kiosk version of CircleDock.
4 - How about reinstall CD? Just delete the folter where CD was placed.
5 - Have you updated your .Net Frameworks?
6 - You CD folder is read-only?
:::> You can drag-n-drop using right-click or left-click, is the same result.