hibernate3.1.2,postgresql 7.4.1......

hi, now in process to complete hibernate tutorial..As mentioned early, i'm using postgres database server and put the jdbc driver to /lib folder. I got error when try to run this command: ant run -Daction=store

the error:
[java] 17:40:42,147 FATAL DriverManagerConnectionProvider:65 - JDBC Driver class not found: org.postgresql.Driver
[java] java.lang.ClassNotFoundException: org.postgresql.Driver
[java] at java.net.URLClassLoader$1.run(URLClassLoader.java:199)

i already check my postgres jdbc driver and it the right one..

and conguration file
<hibernate-configuration>

<session-factory>

<!-- Database connection settings -->
<property name="connection.driver_class">org.postgresql.Driver</property>
<property name="connection.url">jdbc:postgresql:mytestdb</property>
<property name="connection.username">postgres</property>
<property name="connection.password"></property>

<!-- JDBC connection pool (use the built-in) -->
<property name="connection.pool_size">1</property>

<!-- SQL dialect -->
<property name="dialect">org.hibernate.dialect.PostgreSQLDialect</property>

<!-- Enable Hibernate's automatic session context management -->
<property name="current_session_context_class">thread</property>

<!-- Disable the second-level cache -->
<property name="cache.provider_class">org.hibernate.cache.NoCacheProvider</property>

<!-- Echo all executed SQL to stdout -->
<property name="show_sql">true</property>

<!-- Drop and re-create the database schema on startup -->
<property name="hbm2ddl.auto">create</property>

<mapping resource="events/Event.hbm.xml"/>

</session-factory>

</hibernate-configuration>

any help appreciated

1. try to place this jar file to lib folder postgresql-8.0-311.jdbc3.jar for postgres.

2.Refer the below Code Configurations

<session-factory>
<property name="myeclipse.connection.profile">StudentDB</property>
<property name="connection.url">jdbc:postgresql://localhost:5432/StudentDB</property>
<property name="connection.username">postgres</property>
<property name="connection.password">postgres</property>
<property name="connection.driver_class">org.postgresql.Driver</property>
<property name="dialect">org.hibernate.dialect.PostgreSQLDialect</property>
<mapping resource="com/genuitec/hibernate/Student.hbm.xml" />
<mapping resource="com/genuitec/hibernate/Usr.hbm.xml" />

</session-factory>