Ant error: duplicate key value violates unique constraint

‘[java] org.postgresql.util.PSQLException: ERROR: duplicate key value violates unique constraint “bitstreamformatregistry_short_description_key”‘

If you have this error while installing using ant. it is more likely because there is already another copy of data in the database.  your installation is not ‘fresh’.

To continue you must either:

• clear the database, using ‘ant clean_database’ and re-’fresh_install’
• or, if you dont want to lose the data already in the database, you can use ‘ant update’