求救：换新版NHibernate，被卡：

  原来在旧版正常的UserT.hbm.xml现在出错，我卡在这个错误：
    Could not compile the mapping document: NHb_WinApp.ORM.UserT.hbm.xml
求各位求教！出错语句： mCfg.AddAssembly(typeof(UserT).Assembly);UserT.hbm.xml的内容如下：
<?xml version="1.0" encoding="utf-8" ?>
<hibernate-mapping auto-import="true" default-lazy="false" xmlns="urn:nhibernate-mapping-2.2">
 <!--<hibernate-mapping xmlns="urn:nhibernate-mapping-2.0">--> 
<class name="ORM.UserT, NHb_WinApp" table="UserT">
    <id name="UserNameF" type="String" unsaved-value="null">
      <column name="UserNameF" length="50" sql-type="varchar" not-null="true" unique="true" index="PK_UserT_1"/>
      <!--<generator class="native" />-->
      <generator class="assigned" />
    </id>
    <property name="PasswordF" type="String" >
      <column name="PasswordF" length="50" sql-type="varchar" not-null="true"/>
</property>
<property name="RoleIdF" type="Int32">
<column name="RoleIdF" length="4" sql-type="int" not-null="true"/>
</property>
<property name="LastLogonTimeF" type="DateTime">
<column name="LastLogonTimeF" length="8" sql-type="datetime" not-null="false"/>
</property>
<property name="LastLogonMsgF" type="String">
<column name="LastLogonMsgF" length="150" sql-type="nvarchar" not-null="false"/>
</property>
</class>
</hibernate-mapping>  我现在新用NHibernate-2.0.1.GA