more post & Tom

this is the error: I think it doesnt find the postgres driver.
Do you know something about postgresql.jar?
------------------------------------------------------------
Error: 500
Localización: /e2.jsp
Error interno del Servlet:

javax.servlet.ServletException: org.postgresql.Driver
at org.apache.jasper.runtime.PageContextImpl.handlePageException(Unknown Source)
at e2_1._jspService(e2_1.java:121)
at org.apache.jasper.runtime.HttpJspBase.service(Unknown Source)
at javax.servlet.http.HttpServlet.service(HttpServlet.java)
at org.apache.tomcat.facade.ServletHandler.doService(Unknown Source)
at org.apache.tomcat.core.Handler.invoke(Unknown Source)
at org.apache.tomcat.core.Handler.service(Unknown Source)
at org.apache.tomcat.facade.ServletHandler.service(Unknown Source)
at org.apache.tomcat.core.ContextManager.internalService(Unknown Source)
at org.apache.tomcat.core.ContextManager.service(Unknown Source)
at org.apache.tomcat.modules.server.Ajp12Interceptor.processConnection(Unknown Source)
at org.apache.tomcat.util.net.TcpWorkerThread.runIt(Unknown Source)
at org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(Unknown Source)
at java.lang.Thread.run(Thread.java:475)
Causa Raíz:
java.lang.ClassNotFoundException: org.postgresql.Driver
at org.apache.tomcat.util.depend.DependClassLoader.loadClassInternal1(Unknown Source)
at org.apache.tomcat.util.depend.DependClassLoader12$1.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at org.apache.tomcat.util.depend.DependClassLoader12.loadClass(Unknown Source)
at java.lang.ClassLoader.loadClass(ClassLoader.java:243)
at java.lang.Class.forName0(Native Method)
at java.lang.Class.forName(Class.java:120)
at e2_1._jspService(e2_1.java:67)
at org.apache.jasper.runtime.HttpJspBase.service(Unknown Source)
at javax.servlet.http.HttpServlet.service(HttpServlet.java)
at org.apache.tomcat.facade.ServletHandler.doService(Unknown Source)
at org.apache.tomcat.core.Handler.invoke(Unknown Source)
at org.apache.tomcat.core.Handler.service(Unknown Source)
at org.apache.tomcat.facade.ServletHandler.service(Unknown Source)
at org.apache.tomcat.core.ContextManager.internalService(Unknown Source)
at org.apache.tomcat.core.ContextManager.service(Unknown Source)
at org.apache.tomcat.modules.server.Ajp12Interceptor.processConnection(Unknown Source)
at org.apache.tomcat.util.net.TcpWorkerThread.runIt(Unknown Source)
at org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(Unknown Source)
at java.lang.Thread.run(Thread.java:475)