I just cloned the repository yesterday and attempted to run the FirstProject example. It looks like the document property for BaseXmlComponentWriter is not instantiated before ImportAndAppendChild() is called on it.
{FluentNHibernate.Cfg.FluentConfigurationException: An invalid or incomplete configuration was used while creating a SessionFactory. Check PotentialReasons collection, and InnerException for more detail. ---> System.NullReferenceException: Object reference not set to an instance of an object. at FluentNHibernate.Utils.XmlExtensions.ImportAndAppendChild(XmlDocument document, XmlDocument toImport) in D:\Source\ReferenceLibrary\fluent- nhibernate\src\FluentNHibernate\Utils\XmlExtensions.cs:line 78 at FluentNHibernate.MappingModel.Output.BaseXmlComponentWriter.Visit(IComponentMapping componentMapping) in D:\Source\ReferenceLibrary\fluent-nhibernate\src \FluentNHibernate\MappingModel\Output\BaseXmlComponentWriter.cs:line 48 at FluentNHibernate.MappingModel.ClassBased.ReferenceComponentMapping.AcceptVisitor(IMappingModelVisitor visitor) in D:\Source\ReferenceLibrary\fluent-nhibernate\src \FluentNHibernate\MappingModel\ClassBased \ReferenceComponentMapping.cs:line 35 at FluentNHibernate.MappingModel.Output.XmlComponentWriter.Write(IComponentMapping mappingModel) in D:\Source\ReferenceLibrary\fluent-nhibernate\src \FluentNHibernate\MappingModel\Output\XmlComponentWriter.cs:line 32 at FluentNHibernate.MappingModel.Output.XmlClassWriter.Visit(IComponentMapping componentMapping) in D:\Source\ReferenceLibrary\fluent-nhibernate\src \FluentNHibernate\MappingModel\Output\XmlClassWriter.cs:line 112 at FluentNHibernate.MappingModel.MappedMembers.AcceptVisitor(IMappingModelVisitor visitor) in D:\Source\ReferenceLibrary\fluent-nhibernate\src \FluentNHibernate\MappingModel\MappedMembers.cs:line 200 at FluentNHibernate.MappingModel.ClassBased.ClassMappingBase.AcceptVisitor(IMappingModelVisitor visitor) in D:\Source\ReferenceLibrary\fluent-nhibernate\src \FluentNHibernate\MappingModel\ClassBased\ClassMappingBase.cs:line 24 at FluentNHibernate.MappingModel.ClassBased.ClassMapping.AcceptVisitor(IMappingModelVisitor visitor) in D:\Source\ReferenceLibrary\fluent-nhibernate\src \FluentNHibernate\MappingModel\ClassBased\ClassMapping.cs:line 98 at FluentNHibernate.MappingModel.Output.XmlClassWriter.Write(ClassMapping mapping) in D:\Source\ReferenceLibrary\fluent-nhibernate\src \FluentNHibernate\MappingModel\Output\XmlClassWriter.cs:line 21 at FluentNHibernate.MappingModel.Output.XmlHibernateMappingWriter.Visit(ClassMapping classMapping) in D:\Source\ReferenceLibrary\fluent-nhibernate\src \FluentNHibernate\MappingModel\Output \XmlHibernateMappingWriter.cs:line 76 at FluentNHibernate.MappingModel.HibernateMapping.AcceptVisitor(IMappingModelVisitor visitor) in D:\Source\ReferenceLibrary\fluent-nhibernate\src \FluentNHibernate\MappingModel\HibernateMapping.cs:line 42 at FluentNHibernate.MappingModel.Output.XmlHibernateMappingWriter.Write(HibernateMapping mapping) in D:\Source\ReferenceLibrary\fluent-nhibernate\src \FluentNHibernate\MappingModel\Output \XmlHibernateMappingWriter.cs:line 24 at FluentNHibernate.MappingModel.Output.MappingXmlSerializer.BuildXml(HibernateMapping rootMapping) in D:\Source\ReferenceLibrary\fluent-nhibernate\src \FluentNHibernate\MappingModel\Output\MappingXmlSerializer.cs:line 16 at FluentNHibernate.MappingModel.Output.MappingXmlSerializer.Serialize(HibernateMapping mapping) in D:\Source\ReferenceLibrary\fluent-nhibernate\src \FluentNHibernate\MappingModel\Output\MappingXmlSerializer.cs:line 9 at FluentNHibernate.PersistenceModel.Configure(Configuration cfg) in D:\Source\ReferenceLibrary\fluent-nhibernate\src\FluentNHibernate \PersistenceModel.cs:line 261 at FluentNHibernate.Cfg.FluentMappingsContainer.Apply(Configuration cfg) in D:\Source\ReferenceLibrary\fluent-nhibernate\src \FluentNHibernate\Cfg\FluentMappingsContainer.cs:line 140 at FluentNHibernate.Cfg.MappingConfiguration.Apply(Configuration cfg) in D:\Source\ReferenceLibrary\fluent-nhibernate\src \FluentNHibernate\Cfg\MappingConfiguration.cs:line 63 at FluentNHibernate.Cfg.FluentConfiguration.BuildConfiguration() in D:\Source\ReferenceLibrary\fluent-nhibernate\src\FluentNHibernate\Cfg \FluentConfiguration.cs:line 110 --- End of inner exception stack trace --- at FluentNHibernate.Cfg.FluentConfiguration.BuildConfiguration() in D:\Source\ReferenceLibrary\fluent-nhibernate\src\FluentNHibernate\Cfg \FluentConfiguration.cs:line 119 at FluentNHibernate.Cfg.FluentConfiguration.BuildSessionFactory() in D:\Source\ReferenceLibrary\fluent-nhibernate\src\FluentNHibernate \Cfg\FluentConfiguration.cs:line 93 -- You received this message because you are subscribed to the Google Groups "Fluent NHibernate" group. To post to this group, send email to fluent-nhibern...@googlegroups.com. To unsubscribe from this group, send email to fluent-nhibernate+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/fluent-nhibernate?hl=en.