Row_number() not working

I Executed the following query:

select vw.PersonId,vw.CardNumber,vw.CardText,ROW_NUMBER() over (partition by vw.PersonId order by vw.PersonId) as rn from VwExportPerson vw Where vw.AccountId = 22 and (vw.SectionId = 600 or vw.PublishedSecId = 600 ) and (vw.CardStatusLangLvId = 1 or vw.CardStatusLangLvId is null) and (vw.CardLangLvId = 1 or vw.CardLangLvId is null) and (vw.LocLangLvId = 1 or vw.LocLangLvId is null)

and got the exception:
Spring.Data.NHibernate.HibernateQueryException was caught
Message="undefined alias or unknown mapping: ROW_NUMBER [select vw.PersonId,vw.CardNumber,vw.CardText,ROW_NUMBER() over (partition by vw.PersonId order by vw.PersonId) as rn from Risco.Rsp.Ac.AMAC.DomainObjects.VwExportPerson vw Where vw.AccountId = 22 and (vw.SectionId = 600 or vw.PublishedSecId = 600 ) and (vw.CardStatusLangLvId = 1 or vw.CardStatusLangLvId is null) and (vw.CardLangLvId = 1 or vw.CardLangLvId is null) and (vw.LocLangLvId = 1 or vw.LocLangLvId is null)]"
Source="Risco.Rsp.Ac.AMAC.DAO.ExportsMgmt"
QueryString="select vw.PersonId,vw.CardNumber,vw.CardText,ROW_NUMBER() over (partition by vw.PersonId order by vw.PersonId) as rn from Risco.Rsp.Ac.AMAC.DomainObjects.VwExportPerson vw Where vw.AccountId = 22 and (vw.SectionId = 600 or vw.PublishedSecId = 600 ) and (vw.CardStatusLangLvId = 1 or vw.CardStatusLangLvId is null) and (vw.CardLangLvId = 1 or vw.CardLangLvId is null) and (vw.LocLangLvId = 1 or vw.LocLangLvId is null)"
StackTrace:
at Risco.Rsp.Ac.AMAC.DAO.ExportsMgmt.ExportsDAO.FindByQuery(String searchCriteria)
at CompositionAopProxy_3c515189beab4f0dae539ef520299d5d.FindByQuery(String searchCriteria)
at CompositionAopProxy_0e506741a9a2412d82af82e0d55cd662.FindByQuery(String searchCriteria)
at CompositionAopProxy_674a46136ff342268ee5603751b76da0.FindByQuery(String searchCriteria)
at Risco.Rsp.Ac.AMAC.MH.ExportsMgmt.ExportsResultsHandler.Handle(ExportsResults message)
InnerException: NHibernate.QueryException
Message="undefined alias or unknown mapping: ROW_NUMBER [select vw.PersonId,vw.CardNumber,vw.CardText,ROW_NUMBER() over (partition by vw.PersonId order by vw.PersonId) as rn from Risco.Rsp.Ac.AMAC.DomainObjects.VwExportPerson vw Where vw.AccountId = 22 and (vw.SectionId = 600 or vw.PublishedSecId = 600 ) and (vw.CardStatusLangLvId = 1 or vw.CardStatusLangLvId is null) and (vw.CardLangLvId = 1 or vw.CardLangLvId is null) and (vw.LocLangLvId = 1 or vw.LocLangLvId is null)]"
Source="NHibernate"
QueryString="select vw.PersonId,vw.CardNumber,vw.CardText,ROW_NUMBER() over (partition by vw.PersonId order by vw.PersonId) as rn from Risco.Rsp.Ac.AMAC.DomainObjects.VwExportPerson vw Where vw.AccountId = 22 and (vw.SectionId = 600 or vw.PublishedSecId = 600 ) and (vw.CardStatusLangLvId = 1 or vw.CardStatusLangLvId is null) and (vw.CardLangLvId = 1 or vw.CardLangLvId is null) and (vw.LocLangLvId = 1 or vw.LocLangLvId is null)"
StackTrace:
at NHibernate.Hql.Classic.PathExpressionParser.Token(String token, QueryTranslator q)
at NHibernate.Hql.Classic.ParserHelper.Parse(IParser p, String text, String seperators, QueryTranslator q)
at NHibernate.Hql.Classic.SelectParser.Token(String token, QueryTranslator q)
at NHibernate.Hql.Classic.ClauseParser.Token(String token, QueryTranslator q)
at NHibernate.Hql.Classic.ClauseParser.End(QueryTranslator q)
at NHibernate.Hql.Classic.PreprocessingParser.End(QueryTranslator q)
at NHibernate.Hql.Classic.ParserHelper.Parse(IParser p, String text, String seperators, QueryTranslator q)
at NHibernate.Hql.Classic.QueryTranslator.Compile()
at NHibernate.Hql.Classic.QueryTranslator.Compile(IDictionary replacements, Boolean scalar)
at NHibernate.Impl.SessionFactoryImpl.GetQuery(String queryString, Boolean shallow, IDictionary enabledFilters)
at NHibernate.Impl.SessionImpl.GetQueries(String query, Boolean scalar)
at NHibernate.Impl.SessionImpl.Find(String query, QueryParameters parameters, IList results)
at NHibernate.Impl.SessionImpl.Find(String query, QueryParameters parameters)
at NHibernate.Impl.QueryImpl.List()
at Spring.Data.NHibernate.FindHibernateCallback.DoInHibernate(ISession session)
at Spring.Data.NHibernate.HibernateTemplate.Execute(IHibernateCallback action, Boolean exposeNativeSession)
InnerException:

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