No suitable driver error running Tomcat

I'm trying to determine if I want to switch to Tomcat or continue with WebSphere for the app servers we're using and I'm running into a problem getting JDBC to work. I'm trying to use the native JDBC driver and I'm getting the following exception:

2009-08-13 21:25:58,515 [http-8081-1] ERROR com.cl.ecomm.schoolfinder.bo.SchoolsBO - Exception occured in SchoolsBO: Cannot create JDBC driver of class 'com.ibm.db2.jdbc.app.DB2Driver' for connect URL 'jdbc:db2://TLOW400/;transaction isolation=none;translate binary=true;date format=iso;'
org.apache.tomcat.dbcp.dbcp.SQLNestedException: Cannot create JDBC driver of class 'com.ibm.db2.jdbc.app.DB2Driver' for connect URL 'jdbc:db2://TLOW400/;transaction isolation=none;translate binary=true;date format=iso;'
at org.apache.tomcat.dbcp.dbcp.BasicDataSource.createDataSource(BasicDataSource.java:1150)
at org.apache.tomcat.dbcp.dbcp.BasicDataSource.getConnection(BasicDataSource.java:880)
at com.cl.ecomm.schoolfinder.bo.SchoolsBO.getSchoolByEntity(SchoolsBO.java:131)
at com.cl.ecomm.schoolfinder.SchoolEntityLookupServiceSkeleton.findSchoolByEntity(SchoolEntityLookupServiceSkeleton.java:228)
at com.cl.ecomm.schoolfinder.SchoolEntityLookupServiceMessageReceiverInOut.invokeBusinessLogic(SchoolEntityLookupServiceMessageReceiverInOut.java:321)
at org.apache.axis2.receivers.AbstractInOutMessageReceiver.invokeBusinessLogic(AbstractInOutMessageReceiver.java:40)
at org.apache.axis2.receivers.AbstractMessageReceiver.receive(AbstractMessageReceiver.java:114)
at org.apache.axis2.engine.AxisEngine.receive(AxisEngine.java:173)
at org.apache.axis2.transport.http.HTTPTransportUtils.processHTTPPostRequest(HTTPTransportUtils.java:167)
at org.apache.axis2.transport.http.AxisServlet.doPost(AxisServlet.java:142)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:637)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
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:191)
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(CoyoteAdapter.java:293)
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:849)
at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:583)
at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:454)
at java.lang.Thread.run(Thread.java:810)
Caused by:
java.sql.SQLException: No suitable driver
at java.sql.DriverManager.getDriver(DriverManager.java:274)
at org.apache.tomcat.dbcp.dbcp.BasicDataSource.createDataSource(BasicDataSource.java:1143)
... 23 more

I'm running the 32 bit version of JDK 1.5 on V5R4 and Tomcat 6.0.20.

According the documentation I've read, applications should be able to load the native JDBC driver without adding anything to the classpath but that doesn't seem to be the case. I've also tried adding /QIBM/UserData/Java400/ext/db2_classes.jar to Tomcat's classpath (I'm setting it in catalina.sh), copying the driver jar file into Tomcat's lib directory, and copying the driver into the applications lib directory. None of these attempts resolved the issue.

Any help with this would be greatly appreciated.

Thanks,

Matt