Problem loading jdbc driver in servlet, but not in program

I have two simple programs, one is a regular java program, the other
is a java servlet.
When I try to run the servlet, I get "Could not load database driver".
Any ideas on why this
happens?

-Keith

Here are the programs:

1. regular java program:

import java.io.*;
import java.sql.*;
import javax.servlet.*;
import javax.servlet.http.*;

public class DBPhoneLookup {

public static void main (String args[]) throws
ClassNotFoundException, FileNotFoundException, IOException,
SQLException {

try {
Connection con = null;
Statement stmt = null;
ResultSet rs = null;
String url = "jdbc:postgresql:school";
String usr = "postgres";
String pwd = "postgres";

// Load (and therefore register) the Postgres driver
Class.forName("postgresql.Driver");

// Get a connection to the database
con = DriverManager.getConnection(url, usr, pwd);

// Create a Statement object
stmt = con.createStatement();

// Execute an SQL query, get a ResultSet
rs = stmt.executeQuery("Select first_name from students");

// Display the result set as a list
while (rs.next()) {
System.out.println(rs.getString("first_name"));
}

con.close();
}

catch(ClassNotFoundException e) {
System.out.println("Could not load database driver: " +
e.getMessage());
}
}
}

2. servlet program:

import java.io.*;
import java.sql.*;
import javax.servlet.*;
import javax.servlet.http.*;

public class DBPhoneLookup
extends HttpServlet { public void doGet (HttpServletRequest req,
HttpServletResponse res) throws
ServletException, IOException {

Connection con = null;
Statement stmt = null;
ResultSet rs = null;
res.setContentType("text/html");
PrintWriter out = res.getWriter();

try {
String url = "jdbc:postgresql:school";
String usr = "postgres";
String pwd = "postgres";

// Load (and therefore register) the Postgres driver
Class.forName("postgresql.Driver");

// Get a connection to the database
con = DriverManager.getConnection(url, usr, pwd);

// Create a Statement object
stmt = con.createStatement();

// Execute an SQL query, get a ResultSet
rs = stmt.executeQuery("Select first_name from students");

// Display the result set as a list
out.println("");
out.println("");
out.println("");
while (rs.next()) {
out.println(" " + rs.getString("first_name"));
}
out.println(" ");
}

catch(ClassNotFoundException e) {
out.println("Could not load database driver: " +
e.getMessage()); }

catch(SQLException e) {
out.println("SQLException caught: " + e.getMessage()); }

finally {
// Always close the database connection
try { if (con != null) con.close(); }
catch (SQLException ignored) { }
}
}
}