你好，请教一个问题！我用的是jdk6+tomcat5.5.27+myeclipse5.5.1GA,登陆博客时tomcat总是报错
[Microsoft][SQLServer 2000 Driver for JDBC][SQLServer]用户 'sa' 登录失败。
creatConnectionError!
2009-9-11 10:45:05 org.apache.catalina.core.StandardWrapperValve invoke
严重: Servlet.service() for servlet ConsumerServlet threw exception
java.lang.NullPointerException
at com.wy.tool.JDBConnection.executeQuery(JDBConnection.java:52)
at com.wy.dao.ConsumerDao.getConsumerForm(ConsumerDao.java:98)
at com.wy.webiter.ConsumerServlet.checkConsumer(ConsumerServlet.java:169)
at com.wy.webiter.ConsumerServlet.doGet(ConsumerServlet.java:16)
at com.wy.webiter.ConsumerServlet.doPost(ConsumerServlet.java:186)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:647)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:729)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:269)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:188)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:213)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:172)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:117)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:108)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:174)
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:875)
at org.apache.coyote.http11.Http11BaseProtocol$Http11ConnectionHandler.processConnection(Http11BaseProtocol.java:665)
at org.apache.tomcat.util.net.PoolTcpEndpoint.processSocket(PoolTcpEndpoint.java:528)
at org.apache.tomcat.util.net.LeaderFollowerWorkerThread.runIt(LeaderFollowerWorkerThread.java:81)
at org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:689)
at java.lang.Thread.run(Thread.java:619)

折腾了好长时间也没弄好，这是怎么一回事？应该怎么解决？
谢谢！！！！！万分感谢！！！！！