Circular Tags?

Hi, when I click on this tag, I just get a blank screen with "Circular Tag". Does anyone know what it means?

http://www.librarything.com/tag/Australian+Aborigines

A get combined into B, B into C and C into A.
May be a shorter chain (or a longer one) but this is the idea.

Post in Bug Collectors so someone from LT can get them untangled.

Thanks Annie, will do.