I tried the new version of NHibernate 1.2.1 and got some errors with the cache. Am I doing something wrong here or it is a bug?

A first chance exception of type 'System.ArgumentNullException' occurred in mscorlib.dll
All Events Critical: 1 : Timestamp: 2/11/2008 4:08:59 AM
Message: The initialization of the XYZ business logic services failed:
System.ArgumentNullException: Key cannot be null.
Parameter name: key
at System.Collections.Hashtable.get_Item(Object key)
at NHibernate.Impl.SessionFactoryObjectFactory.GetNamedInstance(String name)
at NHibernate.Impl.SessionFactoryImpl.GetRealObject(StreamingContext context)
at System.Runtime.Serialization.ObjectManager.ResolveObjectReference(ObjectHolder holder)
at System.Runtime.Serialization.ObjectManager.DoFixups()
at System.Runtime.Serialization.Formatters.Binary.ObjectReader.Deserialize(HeaderHandler handler, __BinaryParser serParser, Boolean fCheck, Boolean isCrossAppDomain, IMethodCallMessage methodCallMessage)
at System.Runtime.Serialization.Formatters.Binary.BinaryFormatter.Deserialize(Stream serializationStream, HeaderHandler handler, Boolean fCheck, Boolean isCrossAppDomain, IMethodCallMessage methodCallMessage)
at System.Runtime.Serialization.Formatters.Binary.BinaryFormatter.Deserialize(Stream serializationStream)
at Bamboo.Prevalence.Implementation.PendingCommandsEnumerator.NextCommand()
at Bamboo.Prevalence.Implementation.PendingCommandsEnumerator.MoveNext()
at Bamboo.Prevalence.PrevalenceEngine.RecoverCommands(CommandLogReader reader, ExceptionDuringRecoveryHandler handler)
at Bamboo.Prevalence.PrevalenceEngine.RecoverSystem(Type systemType, CommandLogReader reader, ExceptionDuringRecoveryHandler handler)
at Bamboo.Prevalence.PrevalenceEngine..ctor(Type systemType, String prevalenceBase, BinaryFormatter formatter, ExceptionDuringRecoveryHandler handler)
at Bamboo.Prevalence.TransparentPrevalenceEngine..ctor(Type systemType, String prevalenceBase, BinaryFormatter formatter, ExceptionDuringRecoveryHandler handler)
at Bamboo.Prevalence.TransparentPrevalenceEngine..ctor(Type systemType, String prevalenceBase, BinaryFormatter formatter)
at Bamboo.Prevalence.PrevalenceActivator.CreateTransparentEngine(Type systemType, String prevalenceBase, BinaryFormatter formatter)
at Bamboo.Prevalence.PrevalenceActivator.CreateTransparentEngine(Type systemType, String prevalenceBase)
at NHibernate.Caches.Prevalence.PrevalenceCacheProvider.SetupEngine()
at NHibernate.Caches.Prevalence.PrevalenceCacheProvider.Start(IDictionary properties)
at NHibernate.Impl.SessionFactoryImpl..ctor(Configuration cfg, IMapping mapping, Settings settings)
at NHibernate.Cfg.Configuration.BuildSessionFactory()
at XYZ.BusinessLogic.SessionFactory.Initialize() in C:\Users\valo\Documents\Projects\XYZ\XYZ.dev\Main\US\BusinessLogic\NHibernate Utilities\SessionFactory.cs:line 30
at XYZ.BusinessLogic.XYZServiceBase.OnServiceStart() in C:\Users\valo\Documents\Projects\XYZ\XYZ.dev\Main\US\BusinessLogic\Services\ServiceBase.cs:line 27