after upgrading to Nhibernate 3.2.0, the pagination methods of existing projects depending on NH with Oracle databases do not work correctly anymore – they return either zero records, or an incorrect (unexpected) number of them. The problem occurs when using SetFirstResult(int) and SetMaxResults(int) methods of the ICriteria object. Apparently this is caused by a bug in the version 3.2.0. Updating to the currently latest version (3.3.0) resolves the issue.
Further information can be found here.
Hope this helps,