Java Database Connectivity (JDBC)

Hi,
I am getting this error everytime I start my EAR file under the test server in Websphere App. Studio. The server fails to start. I looked thru IBM site, but havent found much help on this. Can someone tell what am I doing wrong ?
I have configured the datasource properly, the deployment code is generated properly...still the websphere studio complains it cant start the testserver... Pls help , I have been struggling to get this working..

Many thanks

[8/22/03 15:07:38:531 GMT+08:00] 6741d5f7 ApplicationMg A WSVR0200I: Starting application: EnrollmentApp
[8/22/03 15:07:38:562 GMT+08:00] 6741d5f7 EJBContainerI I WSVR0207I: Preparing to start EJB jar: EnrollmentAppEJB.jar
[8/22/03 15:07:40:156 GMT+08:00] 6741d5f7 EJBContainerI I WSVR0037I: Starting EJB jar: EnrollmentAppEJB.jar
[8/22/03 15:07:40:578 GMT+08:00] 6741d5f7 ApplicationMg E WSVR0101W: An error occurred starting, EnrollmentApp
[8/22/03 15:07:40:594 GMT+08:00] 6741d5f7 ApplicationMg A WSVR0217I: Stopping application: EnrollmentApp
[8/22/03 15:07:40:734 GMT+08:00] 6741d5f7 EJBContainerI I WSVR0041I: Stopping EJB jar: EnrollmentAppEJB.jar
[8/22/03 15:07:40:781 GMT+08:00] 6741d5f7 ApplicationMg A WSVR0220I: Application stopped: EnrollmentApp
[8/22/03 15:07:45:859 GMT+08:00] 6741d5f7 ApplicationMg A WSVR0217I: Stopping application: IBMUTC
[8/22/03 15:07:45:953 GMT+08:00] 6741d5f7 WebContainer A SRVE0170I: Stopping Web Module: IBM Universal Test Client
[8/22/03 15:07:45:984 GMT+08:00] 6741d5f7 WebGroup I SRVE0180I: [IBM Universal Test Client] [UTC] [Servlet.LOG]: SimpleFileServlet: destroy
[8/22/03 15:07:46:016 GMT+08:00] 6741d5f7 ApplicationMg A WSVR0220I: Application stopped: IBMUTC
[8/22/03 15:07:46:328 GMT+08:00] 6741d5f7 WsServer E WSVR0003E: Server server1 failed to start
com.ibm.ws.exception.RuntimeError
at com.ibm.ws.runtime.component.ApplicationMgrImpl.startApplication(ApplicationMgrImpl.java:257)
at com.ibm.ws.runtime.component.ApplicationMgrImpl.start(ApplicationMgrImpl.java:219)
at com.ibm.ws.runtime.component.ContainerImpl.startComponents(ContainerImpl.java:343)
at com.ibm.ws.runtime.component.ContainerImpl.start(ContainerImpl.java:234)
at com.ibm.ws.runtime.component.ApplicationServerImpl.start(ApplicationServerImpl.java:117)
at com.ibm.ws.runtime.component.ContainerImpl.startComponents(ContainerImpl.java:343)
at com.ibm.ws.runtime.component.ContainerImpl.start(ContainerImpl.java:234)
at com.ibm.ws.runtime.component.ServerImpl.start(ServerImpl.java:180)
at com.ibm.ws.runtime.WsServer.start(WsServer.java:135)
at com.ibm.ws.runtime.WsServer.main(WsServer.java:232)
at java.lang.reflect.Method.invoke(Native Method)
at com.ibm.ws.bootstrap.WSLauncher.main(WSLauncher.java:94)
at com.ibm.etools.websphere.tools.runner.api.ServerRunnerV5$1.run(ServerRunnerV5.java:105)
---- Begin backtrace for nested exception
java.lang.NullPointerException
at com.ibm.ejs.csi.ResRefListImpl.initializeIsolationLevel(ResRefListImpl.java:150)
at com.ibm.ejs.csi.ResRefListImpl.<init>(ResRefListImpl.java:114)
at com.ibm.ws.webcontainer.metadata.WebMetaDataFactory.createMetaData(WebMetaDataFactory.java:127)
at com.ibm.ws.runtime.component.MetaDataMgrImpl.createFactoryMetaData(MetaDataMgrImpl.java:126)
at com.ibm.ws.runtime.component.MetaDataMgrImpl.createMetaData(MetaDataMgrImpl.java:176)
at com.ibm.ws.runtime.component.DeployedModuleImpl.start(DeployedModuleImpl.java:331)
at com.ibm.ws.runtime.component.DeployedApplicationImpl.start(DeployedApplicationImpl.java:504)
at com.ibm.ws.runtime.component.ApplicationMgrImpl.startApplication(ApplicationMgrImpl.java:243)
at com.ibm.ws.runtime.component.ApplicationMgrImpl.start(ApplicationMgrImpl.java:219)
at com.ibm.ws.runtime.component.ContainerImpl.startComponents(ContainerImpl.java:343)
at com.ibm.ws.runtime.component.ContainerImpl.start(ContainerImpl.java:234)
at com.ibm.ws.runtime.component.ApplicationServerImpl.start(ApplicationServerImpl.java:117)
at com.ibm.ws.runtime.component.ContainerImpl.startComponents(ContainerImpl.java:343)
at com.ibm.ws.runtime.component.ContainerImpl.start(ContainerImpl.java:234)
at com.ibm.ws.runtime.component.ServerImpl.start(ServerImpl.java:180)
at com.ibm.ws.runtime.WsServer.start(WsServer.java:135)
at com.ibm.ws.runtime.WsServer.main(WsServer.java:232)
at java.lang.reflect.Method.invoke(Native Method)
at com.ibm.ws.bootstrap.WSLauncher.main(WSLauncher.java:94)
at com.ibm.etools.websphere.tools.runner.api.ServerRunnerV5$1.run(ServerRunnerV5.java:105)

[8/22/03 15:07:46:469 GMT+08:00] 6741d5f7 WsServer E WSVR0009E: Error occurred during startup