Using .NET 1.1, AndroMDA with nHibernate
Database: MYSQL 5.0.27
Using MYSQL connector 1.0.9

This exception occurs randomly on production and everything works fine on reloading the page. We have not encountered this exception while development.

I have checked all hbm mapping files are embedded resource. we have caching enabled and settings as given below:

Caching Entries
<!-- NHibernate caching settings-->
<property name="hibernateEnableCache">true</property>
<property name="hibernateEnableAssociationsCache">false</property>
<property mame="hibernateQueryUseNamedParameters">true</property>
<property name="ehCacheEternal">false</property>
<property name="ehCacheMaxElementsInMemory">100</property>
<property name="ehCacheOverflowToDisk">false</property>
<property name="ehCacheTimeToIdleSeconds">0</property>
<property name="ehCacheTimeToLiveSeconds">172800</property>
<property name="hibernateAssociationCache">read-write</property>
<property name="hibernateEntityCache">read-write</property>
<property name="hibernateUseQueryCache">false</property>


Full Stack Trace

System.Web.HttpUnhandledException: Exception of type System.Web.HttpUnhandledException was thrown. ---> NHibernate.
MappingException: Association references unmapped class: StoryImpl
at NHibernate.Cfg.Binder.BindCollectionSecondPass(XmlNode node, Collection model, IDictionary persistentClasses,
Mappings mappings)
at NHibernate.Cfg.SetSecondPass.SecondPass(IDictionary persistentClasses)
at NHibernate.Cfg.AbstractSecondPass.DoSecondPass(IDictionary persistentClasses)
at NHibernate.Cfg.Configuration.SecondPassCompile()
at NHibernate.Cfg.Configuration.BuildSessionFactory()
at AndroMDA.NHibernateSupport.DefaultSessionManager.BuildSessionFactory()
at AndroMDA.NHibernateSupport.DefaultSessionManager.HandleSessionStart()
at PlanTool.Services.ProjectServiceBase.GetProjectByRsProjectID(String rsProjectID)
at PlanTool.Web.Layout.SA3ToolsLayout.get_ProjectVO()
at PlanTool.Web.Home.HandleLogin()
at PlanTool.Web.Home.Page_Load(Object sender, EventArgs e)
at System.EventHandler.Invoke(Object sender, EventArgs e)
at System.Web.UI.Control.OnLoad(EventArgs e)
at System.Web.UI.Control.LoadRecursive()
at System.Web.UI.Page.ProcessRequestMain()
--- End of inner exception stack trace ---
at System.Web.UI.Page.HandleError(Exception e)
at System.Web.UI.Page.ProcessRequestMain()
at System.Web.UI.Page.ProcessRequest()
at System.Web.UI.Page.ProcessRequest(HttpContext context)
at System.Web.CallHandlerExecutionStep.System.Web.HttpApplication+IExecutionStep.Execute()
at System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously)