Error: Duplicate attribute key found when processing

The following contains a link to possible causes and solutions for errors such:

Errors in the OLAP storage engine: A duplicate attribute key has been found when processing: Table: 'DimTable', Column: 'anAttribute', Value: 'a value'. The attribute is 'anAttribute'

http://ms-olap.blogspot.com/2009/11/duplicate-attribute-key-has-been-found.html