O enum tá mapeado corretamente, tanto é que ele está sendo persistido da forma que se espera.
Quem passa os parametros para a query é o netbeans, eu não sei se eu posso enchertar um parâmetro e passar o valor dele assim, programaticamente 
E sim, itemCirculacaoDocumento.status é um objeto (enum). 
Esse é o mapeamento do campo
/**
*
* @author Leandro
*/
@Entity
@Table(name = "item_circulacao_documento")
@NamedQueries({
@NamedQuery(name = "ItemCirculacaoDocumento.findAll", query = "SELECT i FROM ItemCirculacaoDocumento i"),
@NamedQuery(name = "ItemCirculacaoDocumento.findById", query = "SELECT i FROM ItemCirculacaoDocumento i WHERE i.id = :id"),
@NamedQuery(name = "ItemCirculacaoDocumento.findByObservacao", query = "SELECT i FROM ItemCirculacaoDocumento i WHERE i.observacao = :observacao")})
public class ItemCirculacaoDocumento implements Serializable {
@Transient
private PropertyChangeSupport changeSupport = new PropertyChangeSupport(this);
private static final long serialVersionUID = 1L;
@Id
@SequenceGenerator( name = "item_circulacao_documento_id", sequenceName = "item_circulacao_documento_seq", allocationSize = 1 )
@GeneratedValue( strategy = GenerationType.SEQUENCE, generator = "item_circulacao_documento_id" )
@Column(name = "id")
private Integer id;
@Column(name = "observacao")
private String observacao;
@JoinColumn(name = "idCirculacaoDocumento", referencedColumnName = "id")
@ManyToOne(optional = false)
private CirculacaoDocumento circulacaoDocumento;
@JoinColumn(name = "idDocumento", referencedColumnName = "id")
@ManyToOne(optional = false)
private Documento documento;
@JoinColumn(name = "idCondominio", referencedColumnName = "id")
@ManyToOne(optional = false)
private Condominio condominio;
@Enumerated(EnumType.STRING)
private StatusItemCirculacaoDocumentoEnum status = StatusItemCirculacaoDocumentoEnum.PENDENTE;
...
}
E para clarear um pouco mais, essa é a exceção lançada:
Caused by: Exception [TOPLINK-8015] (Oracle TopLink Essentials - 2.0.1 (Build b09d-fcs (12/06/2007))): oracle.toplink.essentials.exceptions.EJBQLException
Exception Description: Error compiling the query [SELECT DISTINCT c FROM CirculacaoDocumento c, IN (c.itemCirculacaoDocumentoCollection) AS itemCirculacaoDocumento WHERE itemCirculacaoDocumento.status = protosys.entity.enums.StatusItemCirculacaoDocumentoEnum.PENDENTE], line 1, column 210: invalid enum literal, the enum type protosys.entity.enums.StatusItemCirculacaoDocumentoEnum does not have an enum literal PENDENTE.
at oracle.toplink.essentials.exceptions.EJBQLException.invalidEnumLiteral(EJBQLException.java:277)
at oracle.toplink.essentials.internal.parsing.DotNode.validate(DotNode.java:114)
at oracle.toplink.essentials.internal.parsing.Node.validate(Node.java:118)
at oracle.toplink.essentials.internal.parsing.BinaryOperatorNode.validate(BinaryOperatorNode.java:58)
at oracle.toplink.essentials.internal.parsing.EqualsNode.validate(EqualsNode.java:65)
at oracle.toplink.essentials.internal.parsing.WhereNode.validate(WhereNode.java:58)
at oracle.toplink.essentials.internal.parsing.ParseTree.validate(ParseTree.java:235)
at oracle.toplink.essentials.internal.parsing.ParseTree.validate(ParseTree.java:211)
at oracle.toplink.essentials.internal.parsing.ParseTree.validate(ParseTree.java:201)
at oracle.toplink.essentials.internal.parsing.EJBQLParseTree.populateReadQueryInternal(EJBQLParseTree.java:134)
at oracle.toplink.essentials.internal.parsing.EJBQLParseTree.populateQuery(EJBQLParseTree.java:108)
at oracle.toplink.essentials.internal.ejb.cmp3.base.EJBQueryImpl.buildEJBQLDatabaseQuery(EJBQueryImpl.java:219)
at oracle.toplink.essentials.internal.ejb.cmp3.base.EJBQueryImpl.buildEJBQLDatabaseQuery(EJBQueryImpl.java:189)
at oracle.toplink.essentials.internal.ejb.cmp3.base.EJBQueryImpl.buildEJBQLDatabaseQuery(EJBQueryImpl.java:153)
at oracle.toplink.essentials.internal.ejb.cmp3.base.EJBQueryImpl.<init>(EJBQueryImpl.java:114)
at oracle.toplink.essentials.internal.ejb.cmp3.base.EJBQueryImpl.<init>(EJBQueryImpl.java:99)
at oracle.toplink.essentials.internal.ejb.cmp3.EJBQueryImpl.<init>(EJBQueryImpl.java:86)
at oracle.toplink.essentials.internal.ejb.cmp3.EntityManagerImpl.createQuery(EntityManagerImpl.java:204)
... 38 more