Problem wih JDBC driver under Windows XP

Hi all!

I've some problems in connecting to postgreSQL with the JDBC driver from my
JSP page.

I've installed PostgreSQL for Windows, ver. 7.1.2, so I took on the site the
pg72jdbc2.jar file as JDBC driver.

Then I followed all the steps in the documentation at the URL http://jdbc
postgresql.org/doc.html. Because i need to use the jdbc driver with Java
Server Pages, I didn't use the classpath method, but I copyed the driver
directly in the lib/ext directory in my JVM path.

I can connect to the DB with PgAdmin 2, but when I try to connect from my
JSP page, the Tomcat WebServer says:

"java.lang.ClassNotFoundException: org.postgresql.Driver"

What did I forget???

Thanks, Luca.