I am using Cognos 10.1.1. I frequently get the error message that 'the name must be unique' when I want to rename a query from the default to something more meaningful. The strangest thing is that it happens when I do not have another query with the same name. I usually just change it slightly and move on, but I am wondering if other people experience this? It is almost like you are not allowed to name your query the same name as the query subject name in the package.
I have seen this also. In my case I think it was when I named the query the same as a namespace.