http://shervinasgari.blogspot.com/2011/01/remember-that-ordinal-parameters-are-1.html may be related.

looking back at my particular test case:

session.createQuery("delete from X where Y=? ").setParameter(1, uniqueOwnerName)

throw this message:

org.hibernate.QueryParameterException: Position beyond number of declared ordinal parameters. Remember that ordinal parameters are 1-based! Position: 2
at org.hibernate.engine.query.ParameterMetadata.getOrdinalParameterDescriptor(ParameterMetadata.java:81)
at org.hibernate.engine.query.ParameterMetadata.getOrdinalParameterExpectedType(ParameterMetadata.java:87)
at org.hibernate.impl.AbstractQueryImpl.determineType(AbstractQueryImpl.java:444)
at org.hibernate.impl.AbstractQueryImpl.setParameter(AbstractQueryImpl.java:416)
at org.familysearch.digitalarchive.presdb.TapeQueueEntryDB.doneAndDeleteForOwner(TapeQueueEntryDB.java:213)

which seems a bit misleading, since apparently ordinal parameters are 0 based