I have been able to get it working with VFP9.  Here is a copy of my hibernate.cfg.xml file which allows me to connect - 
Code:
<?xml version="1.0" encoding="utf-8" ?>
<hibernate-configuration xmlns="urn:nhibernate-configuration-2.2" >
  <session-factory>
    <property name="connection.provider">NHibernate.Connection.DriverConnectionProvider</property>
    <property name="dialect">NHibernate.Dialect.MsSql2000Dialect</property>
    <property name="connection.driver_class">NHibernate.Driver.OleDbDriver</property>
    <property name="connection.connection_string">Provider=VFPOLEDB.1;Data Source=C:\data_directory;Password="";Collating Sequence=MACHINE</property>
    <property name="proxyfactory.factory_class">NHibernate.ByteCode.Castle.ProxyFactoryFactory, NHibernate.ByteCode.Castle</property>
    <property name="show_sql">true</property>
  </session-factory>
</hibernate-configuration>
Hope this helps.