Couier keeps displaying the message below when packaging, it did manage to fix it self for a while but now is back.  Any ideas?

error:Umbraco.Courier.Core.Exceptions.PackageException: Unable to load item with id '11202ef9-5b44-4e7d-aae6-3cfab34f4586' from provider 'Documents' ---> Umbraco.Courier.Core.Exceptions.RetrieveException: Error retrieving item [11202ef9-5b44-4e7d-aae6-3cfab34f4586] from provider [d8e6ad83-e73a-11df-9492-0800200c9a66]. ---> NHibernate.HibernateException: could not reassociate uninitialized transient collection at NHibernate.Event.Default.ProxyVisitor.ReattachCollection(IPersistentCollection collection, CollectionType type) at NHibernate.Event.Default.WrapVisitor.ProcessCollection(Object collection, CollectionType collectionType) at NHibernate.Event.Default.AbstractVisitor.ProcessValue(Object value, IType type) at NHibernate.Event.Default.WrapVisitor.ProcessValue(Int32 i, Object[] values, IType[] types) at NHibernate.Event.Default.AbstractVisitor.ProcessEntityPropertyValues(Object[] values, IType[] types) at NHibernate.Event.Default.DefaultFlushEntityEventListener.WrapCollections(IEventSource session, IEntityPersister persister, IType[] types, Object[] values) at NHibernate.Event.Default.DefaultFlushEntityEventListener.OnFlushEntity(FlushEntityEvent event) at NHibernate.Event.Default.AbstractFlushingEventListener.FlushEntities(FlushEvent event) at NHibernate.Event.Default.AbstractFlushingEventListener.FlushEverythingToExecutions(FlushEvent event) at NHibernate.Event.Default.DefaultAutoFlushEventListener.OnAutoFlush(AutoFlushEvent event) at NHibernate.Impl.SessionImpl.AutoFlushIfRequired(ISet`1 querySpaces) at NHibernate.Impl.SessionImpl.List(CriteriaImpl criteria, IList results) at NHibernate.Impl.CriteriaImpl.List(IList results) at NHibernate.Impl.CriteriaImpl.List[T]() at Umbraco.Courier.Persistence.V4.NHibernate.Helpers.CmsNodeHelper.GetNode(Guid uniqueId, ISession session) in c:\Program Files (x86)\teamcity\buildAgent\work\650bafc4b83aa858\Core\Umbraco.Courier.Persistence.NHibernate\Helpers\CmsNodeHelper.cs:line 69 at Umbraco.Courier.Persistence.V4.NHibernate.Helpers.DocumentHelper.Get(Guid uniqueId, ISession session) in c:\Program Files (x86)\teamcity\buildAgent\work\650bafc4b83aa858\Core\Umbraco.Courier.Persistence.NHibernate\Helpers\DocumentHelper.cs:line 22 at Umbraco.Courier.Persistence.V4.NHibernate.Persisters.DocumentItem.RetrieveItem[T](ItemIdentifier itemId) in c:\Program Files (x86)\teamcity\buildAgent\work\650bafc4b83aa858\Core\Umbraco.Courier.Persistence.NHibernate\Persisters\Document.cs:line 141 at Umbraco.Courier.Core.ItemCrudProvider.RetrieveItem[T](ItemIdentifier itemId) --- End of inner exception stack trace --- at Umbraco.Courier.Core.ItemCrudProvider.RetrieveItem[T](ItemIdentifier itemId) at Umbraco.Courier.ItemProviders.DocumentItemProvider.HandlePack(ItemIdentifier id) in c:\Program Files (x86)\teamcity\buildAgent\work\650bafc4b83aa858\Core\Umbraco.Courier.Providers\ItemProviders\ContentItemProvider.cs:line 79 at Umbraco.Courier.Core.ItemProvider.Package(ItemIdentifier id) at Umbraco.Courier.RepositoryProviders.Local.Package(ItemIdentifier itemId) in c:\Program Files (x86)\teamcity\buildAgent\work\650bafc4b83aa858\Contrib\Providers\Umbraco.Courier.RepositoryProviders\Local\Local.cs:line 250 at Umbraco.Courier.Core.Packaging.RevisionPackaging.#Ab(ItemIdentifier itemId, ItemProvider provider, QueuedItemIdentifier itemInQueue) --- End of inner exception stack trace --- at Umbraco.Courier.Core.Packaging.RevisionPackaging.#Ab(ItemIdentifier itemId, ItemProvider provider, QueuedItemIdentifier itemInQueue) at Umbraco.Courier.Core.Packaging.RevisionPackaging.#oj() at Umbraco.Courier.Core.Packaging.RevisionPackaging.Package() at Umbraco.Courier.Core.Tasks.PackagingTask.Run() at Umbraco.Courier.Core.TaskManager.#Lb(IRevisionTask value) 28/02/2013 16:17:42