I have made a sample application and when i try to compile it, It gives me the following error message:

The ProxyFactoryFactory was not configured.
Initialize 'proxyfactory.factory_class' property of the session-factory configuration section with one of the available NHibernate.ByteCode providers.
Example:
<property name='proxyfactory.factory_class'>NHibernate.ByteCode.LinFu.ProxyFactoryFactory, NHibernate.ByteCode.LinFu</property>
Example:
<property name='proxyfactory.factory_class'>NHibernate.ByteCode.Castle.ProxyFactoryFactory, NHibernate.ByteCode.Castle</property>

Please tell me exactly where the problem is. I am new to NHibernate..
Thank you so much in advance...

Hibernate uses object proxies for lazy loading. In short, they are derived objects from your mapped classes which are instantiated from hibernate. When you access your object through the proxy hibernate makes sure that the necessary data gets loaded. If you do not use castle, you should use

<property name='proxyfactory.factory_class'>NHibernate.ByteCode.LinFu.ProxyFactoryFactory, NHibernate.ByteCode.LinFu</property>


http://nhforge.org/blogs/nhibernate/archive/2008/11/09/nh2-1-0-bytecode-providers.aspx