急死人了，IbatisNet中Dao总是报错

dao.config文件:<?xml version="1.0" encoding="utf-8"?>
<daoConfig  xmlns="http://ibatis.apache.org/dataAccess" 
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">

<context id="SqlMapDao" default="true">
     
    <database>     
<provider name="OleDb1.1"/>    
<dataSource name="DM" connectionString="Provider=DMOLEDB.1; Data Source=localhost; DataBase=NEWS; User ID=NEWSLOGIN; Password=NEWSLOGIN;"/>
     </database>        <daoSessionHandler id="SqlMap">
           <property name="resource" value="SqlMap.config"/>
       </daoSessionHandler>

<daoFactory assembly="DMNews.Persistense">
<dao name="ICategory" 
implementation="DMNews.Persistence.CategorySqlMapDao"/>
<dao name="IArticle" 
implementation="DMNews.Persistence.ArticleSqlMapDao"/>
</daoFactory>
</context>

</daoConfig>在使用
DaoManager daoManager=DaoManager.GetInstance("SqlMapDao");
SqlMapDaoSession sqlMapDaoSession=(SqlMapDaoSession)daoManager.LocalDaoSession;
return sqlMapDaoSession.SqlMap;总是说未将对像设置到实例（第二句出错），数据库那样的写法是没错的，那么是什么问题了，请大家帮我