Win 2003, Courier 2.7.3, umbraco v 4.7.1.1 (Assembly version: 1.0.4393.24044), SQL 2008

We upgraded Courier last week and was tested and working, but now have some catastrophic errors - It's importand that we fix these asap so any help from anyone would be VERY much appreciated

Courier any content: 

error:Umbraco.Courier.Core.Exceptions.PackageException: Unable to load item with id 'edbfa2f8-f0d5-491c-a765-f526b0acff9c' from provider 'Documents' ---> Umbraco.Courier.Core.Exceptions.RetrieveException: Error retrieving item [edbfa2f8-f0d5-491c-a765-f526b0acff9c] 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.WrapVisitor.ProcessValue(Int32 i, Object[] values, IType[] types) at NHibernate.Event.Default.AbstractVisitor.ProcessEntityPropertyValues(Object[] values, IType[] types) 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.DocumentHelper.Get(Guid uniqueId, ISession session) in c:\Program Files (x86)\teamcity\buildAgent\work\650bafc4b83aa858\Core\Umbraco.Courier.Persistence.NHibernate\Helpers\DocumentHelper.cs:line 23 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 80 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.TaskManager.#Lb(IRevisionTask value) 04/03/2013 15:19:00

YSOD in the Courier section of the CMS:

Server Error in '/' Application.
could not reassociate uninitialized transient collection
Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code. 
Exception Details: NHibernate.HibernateException: could not reassociate uninitialized transient collection
Source Error: 
An unhandled exception was generated during the execution of the current web request. Information regarding the origin and location of the exception can be identified using the exception stack trace below.
Stack Trace: 

[HibernateException: could not reassociate uninitialized transient collection]
   NHibernate.Event.Default.ProxyVisitor.ReattachCollection(IPersistentCollection collection, CollectionType type) +416
   NHibernate.Event.Default.WrapVisitor.ProcessCollection(Object collection, CollectionType collectionType) +113
   NHibernate.Event.Default.WrapVisitor.ProcessValue(Int32 i, Object[] values, IType[] types) +132
   NHibernate.Event.Default.AbstractVisitor.ProcessEntityPropertyValues(Object[] values, IType[] types) +83
   NHibernate.Event.Default.DefaultFlushEntityEventListener.OnFlushEntity(FlushEntityEvent event) +224
   NHibernate.Event.Default.AbstractFlushingEventListener.FlushEntities(FlushEvent event) +448
   NHibernate.Event.Default.AbstractFlushingEventListener.FlushEverythingToExecutions(FlushEvent event) +275
   NHibernate.Event.Default.DefaultAutoFlushEventListener.OnAutoFlush(AutoFlushEvent event) +83
   NHibernate.Impl.SessionImpl.AutoFlushIfRequired(ISet`1 querySpaces) +474
   NHibernate.Impl.SessionImpl.List(CriteriaImpl criteria, IList results) +782
   NHibernate.Impl.CriteriaImpl.List(IList results) +63
   NHibernate.Impl.CriteriaImpl.List() +79
   Umbraco.Courier.Persistence.V4.NHibernate.Helpers.CmsNodeHelper.GetNodeChildren(Guid uniqueId, Guid nodeObjectType, ISession session) in c:\Program Files (x86)\teamcity\buildAgent\work\650bafc4b83aa858\Core\Umbraco.Courier.Persistence.NHibernate\Helpers\CmsNodeHelper.cs:144
   Umbraco.Courier.Persistence.V4.NHibernate.Persisters.DataTypeItem.AvailableItems(ItemIdentifier itemId) in c:\Program Files (x86)\teamcity\buildAgent\work\650bafc4b83aa858\Core\Umbraco.Courier.Persistence.NHibernate\Persisters\Datatype.cs:155
   Umbraco.Courier.Core.ItemCrud.AvailableItems() +73
   Umbraco.Courier.UI.Pages.SimpleRevisionDeploy.#4e(ItemProvider p) +21
   System.Linq.WhereListIterator`1.MoveNext() +165
   System.Web.UI.WebControls.ListControl.PerformDataBinding(IEnumerable dataSource) +776
   System.Web.UI.WebControls.ListControl.PerformSelect() +51
   Umbraco.Courier.UI.Pages.SimpleRevisionDeploy.Page_Load(Object sender, EventArgs e) +287
   System.Web.Util.CalliHelper.EventArgFunctionCaller(IntPtr fp, Object o, Object t, EventArgs e) +25
   System.Web.UI.Control.LoadRecursive() +71
   System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +3064
Version Information: Microsoft .NET Framework Version:4.0.30319; ASP.NET Version:4.0.30319.272

Have tried the usual suspects (recycle app pools / IIS / SQL Server) but no joy. 

Thanks again. 

Bill