<?xml version="1.0" encoding="utf-8" ?>
<hibernate-mapping xmlns="urn:nhibernate-mapping-2.0" default-access="field.pascalcase-m-underscore" assembly="TEST.Business" namespace="TEST.Business">
  <class name="TEST.Business.Subjects.Subject" table="Subject" lazy="false">
    <id name="Id" type="Int32" column="id_Subject" unsaved-value="0">
      <generator class="native" />
    </id>
    <property name="CreatedOn" type="DateTime" not-null="true" />
    <many-to-one name="Rating" class="TEST.Business.Subjects.SubjectRating" column="id_Rating" not-null="true" />
    <property name="IsActive" type="Boolean" not-null="true" />
    <property name="Keywords" type="String" />
  </class>
</hibernate-mapping>

NHibernate.HibernateException was unhandled
  Message="Creating a proxy instance failed"
  Source="NHibernate"
  StackTrace:
       at NHibernate.Proxy.CastleProxyFactory.GetProxy(Object id, ISessionImplementor session) in C:\Documents and Settings\sousek\My Documents\Visual Studio 2005\Projects\Sprinx.Framework\NHibernate\Proxy\CastleProxyFactory.cs:line 71
       at NHibernate.Persister.AbstractEntityPersister.CreateProxy(Object id, ISessionImplementor session) in C:\Documents and Settings\sousek\My Documents\Visual Studio 2005\Projects\Sprinx.Framework\NHibernate\Persister\AbstractEntityPersister.cs:line 1494
       at NHibernate.Impl.SessionImpl.DoLoadByClass(Type clazz, Object id, Boolean checkDeleted, Boolean allowProxyCreation) in C:\Documents and Settings\sousek\My Documents\Visual Studio 2005\Projects\Sprinx.Framework\NHibernate\Impl\SessionImpl.cs:line 2399
       at NHibernate.Impl.SessionImpl.Load(Type clazz, Object id) in C:\Documents and Settings\sousek\My Documents\Visual Studio 2005\Projects\Sprinx.Framework\NHibernate\Impl\SessionImpl.cs:line 2265
       at SF.BusinessSupport.BusinessEntityFactory`1.FindById(Int32 id, FetchMethod method) in C:\Documents and Settings\sousek\My Documents\Visual Studio 2005\Projects\Sprinx.Framework\SF.BusinessSupport\BusinessEntityFactory.cs:line 29
       at SF.BusinessSupport.BusinessEntityFactory`1.FindById(Int32 id) in C:\Documents and Settings\sousek\My Documents\Visual Studio 2005\Projects\Sprinx.Framework\SF.BusinessSupport\BusinessEntityFactory.cs:line 38
       at TEST.Console.Program.Main(String[] args) in C:\Documents and Settings\sousek\My Documents\Visual Studio 2005\Projects\Sprinx.Framework\TEST.Console\Program.cs:line 25
       at System.AppDomain.nExecuteAssembly(Assembly assembly, String[] args)
       at System.AppDomain.ExecuteAssembly(String assemblyFile, Evidence assemblySecurity, String[] args)
       at Microsoft.VisualStudio.HostingProcess.HostProc.RunUsersAssembly()
       at System.Threading.ThreadHelper.ThreadStart_Context(Object state)
       at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
       at System.Threading.ThreadHelper.ThreadStart()

Inner exception: "Argument 'baseClass' must be a concrete class"