Question: I've build my WinForm app on windows machine and the app is working
ok. When I user nhibernate 1.2.1 the app also worked on linux machine
using mono, but now when i upgraded app to nhibernate 2.0.1 it works
only in windows.
I've get error:
 NHibernate.InvalidProxyTypeException: The following types may not be
used as proxies:
xxxx.Data.Dao.Credit : method obj\_address should be virtual
......
Can anyone help me with this problem?

Answer: 
You can try and disable the NHibernate Config proxy validator. it seems to not work with mono.

You can do this by adding:
`<property name="use_proxy_validator">false</property>` in your app/web.config nhibernate section.

For an example config with this property set, see here:
<http://www.mail-archive.com/nhusers@googlegroups.com/msg02109.html>

or modify this:

```
<?xml version="1.0"?>
<configuration>
  <configSections>
    <section name="hibernate-configuration"
             type="NHibernate.Cfg.ConfigurationSectionHandler, NHibernate" />
  </configSections>

  <hibernate-configuration xmlns="urn:nhibernate-configuration-2.2">
    <session-factory>
        <!--
      <property name="dialect">NHibernate.Dialect.MsSql2005Dialect</property>
      <property name="connection.provider">NHibernate.Connection.DriverConnectionProvider</property>
      <property name="connection.driver_class">NHibernate.Driver.SqlClientDriver</property>
      <property name="connection.connection_string">Data Source=YOUR_DB_SERVER;Database=Northwind;User ID=YOUR_USERNAME;Password=YOUR_PASSWORD;</property>
      <property name="connection.isolation">ReadCommitted</property>
      <property name="default_schema">Northwind.dbo</property>
          -->
        <!--
      <property name="dialect">NHibernate.Dialect.SQLiteDialect</property>
      <property name="connection.provider">NHibernate.Connection.DriverConnectionProvider</property>
      <property name="connection.driver_class">NHibernate.Driver.SQLiteDriver</property>
      <property name="connection.connection_string">Data Source=nhibernate.db;Version=3</property>
      <property name="query.substitutions">true=1;false=0</property>
          -->
          <!-- mysql
      <property name="dialect">NHibernate.Dialect.MySQLDialect</property>
      <property name="connection.provider">NHibernate.Connection.DriverConnectionProvider</property>
      <property name="connection.driver_class">NHibernate.Driver.MySqlDataDriver</property>
      <property name="connection.connection_string">Database=test</property>
          -->
          <property name="connection.provider">NHibernate.Connection.DriverConnectionProvider</property>
          <property name="connection.driver_class">NHibernate.Driver.NpgsqlDriver</property>
          <property name="connection.connection_string">Server=localhost;database=test;User id=jrwren;password=yourpasswordhere.</property>
          <property name="dialect">NHibernate.Dialect.PostgreSQLDialect</property>
          <property name="use_proxy_validator">false</property>
      <!-- HBM Mapping Files -->
      <mapping assembly="Test.exe" />
    </session-factory>
  </hibernate-configuration>

</configuration>

```
This might be of interest:

<http://softwaredevscott.spaces.live.com/blog/cns!1A9E939F7373F3B7!251.entry>