the issue is related to duplicated values .
if you try to duplicate a column value which have unique constraints(contains only unique values) on it it will throw this error.
I ran into this same problem, and this is one the very few pages I found in my searches. I've outlined my process (and confusion) at http://www.awarren.ca/2013/07/import-problems-with-application-express-4-2-2/
Ultimately, I had success insuring no page contained multiple interactive report definitions, even if those definitions have mutually exclusive rendering conditions.
I hope helps the next person who runs into this!