MYSQL 求高手帮助

各位高手好。小弟学习JAVA不久，然后再用MYSQL数据库。
由于是用别人的的范例学习，所以出现很多奇怪的问题
我用自己的MYSQL 服务器，然后把别人的数据库导进来。然后出现版本问题。
问题如下
Table './db_librarysys/tb_manager' was created with a different version of MySQL and cannot be read
2010-4-28 22:44:00 org.apache.struts.action.RequestProcessor processException
警告: Unhandled Exception thrown: class java.lang.NullPointerException
2010-4-28 22:44:00 org.apache.catalina.core.StandardWrapperValve invoke
严重: Servlet.service() for servlet action threw exception
java.lang.NullPointerException
 at com.dao.ManagerDAO.checkManager(ManagerDAO.java:75)
 at com.action.Manager.managerLogin(Manager.java:51)
 at com.action.Manager.execute(Manager.java:24)
 at org.apache.struts.action.RequestProcessor.processActionPerform(RequestProcessor.java:431)
 at org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:236)
 at org.apache.struts.action.ActionServlet.process(ActionServlet.java:1196)
 at org.apache.struts.action.ActionServlet.doPost(ActionServlet.java:432)
 at javax.servlet.http.HttpServlet.service(HttpServlet.java:710)
 at javax.servlet.http.HttpServlet.service(HttpServlet.java:803)
 at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)
 at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
 at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:233)
 at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:175)
 at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:128)
 at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)
 at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
 at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAd