使用SSH框架编写WEB应用部署到Tomcat上出错

之前部署在TOMCAT6.0.29上，因为6.0.29有内存收集机制导致部署不上去，所以改为部署到5.5上，结果部署运行的时候出现如下错误（首页没出错，但是输入了用户名和密码就出现错误）：
HTTP Status 500 -
type Exception report
message
description The server encountered an internal error () that prevented it from fulfilling this request.
exception
org.springframework.transaction.CannotCreateTransactionException: Could not open Hibernate Session for transaction; nested exception is org.hibernate.exception.GenericJDBCException: Could not open connection
org.springframework.orm.hibernate4.HibernateTransactionManager.doBegin(HibernateTransactionMan
com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:98)
r.java:91)
com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244)
………………
com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244)
com.opensymphony.xwork2.interceptor.PrepareInterceptor.doIntercept(PrepareInterceptor.java:171)
com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:98)
com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244)
com.opensymphony.xwork2.interceptor.I18nInterceptor.intercept(I18nInterceptor.java:139)

note The full stack trace of the root cause is available in the Apache Tomcat/6.0.29 logs.
Apache Tomcat/6.0.29

我用的是5.5版本，但是错误显示确实使用的6.0.29版本，也就是之前我安装Tomcat的版本。我即使删除了原来版本Tomcat也不行。