C# – An association from the table X refers to an unmapped class: System.Guid

I have this class:

public class AttachmentLocation
{
    #region properties

    public virtual Guid UserId { get; set; }

    public virtual Guid LocationId { get; set; }

    public virtual long IndexInLocation { get; set; }

    #endregion

    #region contained foreign objects

    public virtual Attachment Attachment { get; set; }

    #endregion


    #region Methods need to override for CompositeId

    public override bool Equals(object obj)
    {
        if (obj == null)
            return false;
        var t = obj as AttachmentLocation;
        if (t == null)
            return false;
        if (UserId == t.UserId && LocationId == t.LocationId && Attachment.Id == t.Attachment.Id)
            return true;
        return false;
    }

    public override int GetHashCode()
    {
        return (UserId + "|" + LocationId + "|" + Attachment.Id).GetHashCode();
    }

    #endregion

}

I have this Fluent Mapping:

public class AttachmentLocaionMap : ClassMap<AttachmentLocation>
{
    public AttachmentLocaionMap()
    {
        Table("Metadata_AttachmentLocation");
        CompositeId()
            .KeyReference(x => x.UserId, "UserId")
            .KeyReference(x => x.Attachment.Id, "AttachmentId")
            .KeyReference(x => x.LocationId, "LocationId");
        Map(x => x.IndexInLocation).Not.Nullable();
        Map(x => x.LocationId).Not.Nullable();

        HasOne(x => x.Attachment);
    }
}

which I register:

SessionFactory = Fluently.Configure(configuration).Mappings(m =>
{
    m.FluentMappings.AddFromAssemblyOf<AttachmentLocaionMap>();           
    m.FluentMappings.AddFromAssemblyOf<FriendDetailsMap>();
}).BuildSessionFactory();

I get this runtime error:

An association from the table Metadata_AttachmentLocation refers to an
unmapped class: System.Guid

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.MappingException: An association from
the table Metadata_AttachmentLocation refers to an unmapped class:
System.Guid

Source Error:

Line 19: Line 20: Line 21: SessionFactory =
Fluently.Configure(configuration).Mappings(m => Line 22: {
Line 23:
m.FluentMappings.AddFromAssemblyOf();

Source File: C:\Users\elad\Documents\Visual Studio
2010\Projects\SVN\UGI\Ugi\Infrastructure\Dal\Adapters\NHibernateAdapter\NHibernateHelper.cs
Line: 21

Stack Trace:

[MappingException: An association from the table
Metadata_AttachmentLocation refers to an unmapped class: System.Guid]
NHibernate.Cfg.Configuration.LogAndThrow(Exception exception) in
d:\CSharp\NH\NH\nhibernate\src\NHibernate\Cfg\Configuration.cs:342
NHibernate.Cfg.Configuration.SecondPassCompileForeignKeys(Table table,
ISet done) in
d:\CSharp\NH\NH\nhibernate\src\NHibernate\Cfg\Configuration.cs:1169
NHibernate.Cfg.Configuration.SecondPassCompile() in
d:\CSharp\NH\NH\nhibernate\src\NHibernate\Cfg\Configuration.cs:1120
NHibernate.Cfg.Configuration.BuildSessionFactory() in
d:\CSharp\NH\NH\nhibernate\src\NHibernate\Cfg\Configuration.cs:1249
FluentNHibernate.Cfg.FluentConfiguration.BuildSessionFactory() in
d:\Builds\FluentNH-v1.x-nh3\src\FluentNHibernate\Cfg\FluentConfiguration.cs:227

[FluentConfigurationException: An invalid or incomplete configuration
was used while creating a SessionFactory. Check PotentialReasons
collection, and InnerException for more detail.

• Database was not configured through Database method. ]
  FluentNHibernate.Cfg.FluentConfiguration.BuildSessionFactory() in
  d:\Builds\FluentNH-v1.x-nh3\src\FluentNHibernate\Cfg\FluentConfiguration.cs:232
  Ugi.Infrastructure.Dal.Adapters.NHibernateAdapter.NHibernateHelper.OpenSession()
  in C:\Users\elad\Documents\Visual Studio
  2010\Projects\SVN\UGI\Ugi\Infrastructure\Dal\Adapters\NHibernateAdapter\NHibernateHelper.cs:21
  Ugi.Infrastructure.Dal.Adapters.NHibernateAdapter.NHibernateHelper.GetSession()
  in C:\Users\elad\Documents\Visual Studio
  2010\Projects\SVN\UGI\Ugi\Infrastructure\Dal\Adapters\NHibernateAdapter\NHibernateHelper.cs:36
  Ugi.Infrastructure.Dal.Adapters.NHibernateAdapter.NHibernateDal1..ctor()
in C:\Users\elad\Documents\Visual Studio
2010\Projects\SVN\UGI\Ugi\Infrastructure\Dal\Adapters\NHibernateAdapter\NHibernateDal.cs:16
Ugi.Infrastructure.Dal.Adapters.NHibernateAdapter.NHibernateDalFactory.GetDal()
in C:\Users\elad\Documents\Visual Studio
2010\Projects\SVN\UGI\Ugi\Infrastructure\Dal\Adapters\NHibernateAdapter\NHibernateDalFactory.cs:17
Ugi.Server.Sources.Logic.SourcesService..ctor() in
C:\Users\elad\Documents\Visual Studio
2010\Projects\SVN\UGI\Ugi\Server\Sources\Logic\SourcesService.cs:36
BuildUp_Ugi.Server.Sources.Logic.SourcesService(IBuilderContext ) +153
Microsoft.Practices.ObjectBuilder2.DynamicMethodBuildPlan.BuildUp(IBuilderContext
context) in
c:\EntLib\UnityTemp\Compile\Unity\Unity\Src\ObjectBuilder\Strategies\BuildPlan\DynamicMethod\DynamicMethodBuildPlan.cs:37
Microsoft.Practices.ObjectBuilder2.BuildPlanStrategy.PreBuildUp(IBuilderContext
context) in
c:\EntLib\UnityTemp\Compile\Unity\Unity\Src\ObjectBuilder\Strategies\BuildPlan\BuildPlanStrategy.cs:43
Microsoft.Practices.ObjectBuilder2.StrategyChain.ExecuteBuildUp(IBuilderContext
context) in
c:\EntLib\UnityTemp\Compile\Unity\Unity\Src\ObjectBuilder\Strategies\StrategyChain.cs:110
Microsoft.Practices.Unity.UnityContainer.DoBuildUp(Type t, Object
existing, String name, IEnumerable1 resolverOverrides) in
  c:\EntLib\UnityTemp\Compile\Unity\Unity\Src\UnityContainer.cs:512

[ResolutionFailedException: Resolution of the dependency failed, type
= "Ugi.Common.Model.Sources.ISourcesService", name = "(none)". Exception occurred while: Calling constructor
Ugi.Server.Sources.Logic.SourcesService(). Exception is:
FluentConfigurationException – An invalid or incomplete configuration
was used while creating a SessionFactory. Check PotentialReasons
collection, and InnerException for more detail.

• Database was not configured through Database method.

How can I fix that?

TIA