EJB 3.0的一个依赖异常，把我给害惨了~~~

今天使用MyEclipse 7.1.0的JBoss 4.2.2GA在RedHat v9.0下部署一个EJB 3.0的练习项目出现如下异常：
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20:19:02,753 ERROR [URLDeploymentScanner] Incomplete Deployment listing:

--- MBeans waiting for other MBeans ---
ObjectName: persistence.units:jar=chapter03_exec.jar,unitName=chapter03_execPU
  State: NOTYETINSTALLED
  I Depend On:
    jboss.jca:name=MySql,service=DataSourceBinding

ObjectName: persistence.units:jar=chapter03_exec.jar,unitName=chapter03_execPU
  State: NOTYETINSTALLED
  I Depend On:
    jboss.jca:name=MySql,service=DataSourceBinding
  Depends On Me:
    jboss.j2ee:jar=chapter03_exec.jar,name=StockBean,service=EJB3

ObjectName: jboss.j2ee:jar=chapter03_exec.jar,name=StockBean,service=EJB3
  State: NOTYETINSTALLED
  I Depend On:
    persistence.units:jar=chapter03_exec.jar,unitName=chapter03_execPU

--- MBEANS THAT ARE THE ROOT CAUSE OF THE PROBLEM ---
ObjectName: jboss.jca:name=MySql,service=DataSourceBinding
  State: NOTYETINSTALLED
  Depends On Me:
    persistence.units:jar=chapter03_exec.jar,unitName=chapter03_execPU

    persistence.units:jar=chapter03_exec.jar,unitName=chapter03_execPU

===================================================================
如下工作已经完成：
1,Copy "mysql-connector-java-5.0.8-bin.jar"到"#\jboss-4.2.2.GA\server\default\lib"下
2,Copy "mysql-ds.xml"到"#\jboss-4.2.2.GA\server\default\deploy"下
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查了源代码，也看了配置文件，还求了Google大神，还是没看出哪里错了，郁闷~~~
忙活了好大一会，才发现配置文件persistence.xml中的数据源写错了，我写成这样：
java:/MySql
正确的写法应该是：
java:/MySqlDS
唉，真拿自己没办法了，怎么老是犯这种低级错误呢？粗心能害死人啊！
一定要细心，细心，细心，再细心。。。