SUBSONIC loadbykey in Oracle 11 error

Question

Does anyone knows why when I run the next command comes the message error

ORA-00904: "SYSTEM"."SITUACAO"."IDSITUACAO": identificador inválido

The obj.save() or SqlQuery qry = new Select().From("SITUACAO") run perfect !!

only loadbykey() get an error .

THE CODE : Situacao x = new Situacao(); x.LoadByKey(1);

thanks any help .