No SuitableDriver error while inserting through Servlet ,while No error through A Java application

Dear Sir,

I am trying to run UpdateQuery from a redhatlinux 6.2 server with Apache
Jserv with PostGres.

When I try a simple Insert statement or a Query statement from a Java
Applicationit works fine,
But when i try to do that through a servlet.
It gives me No Suitable Driver.
I have my PostGreSQL Driver in the ext directory of jre/lib/ext/

the following code tries to make a connection and inserts the statements

try {Class.forName("org.postgresql.Driver");
}

catch(ClassNotFoundException ex){System.err.println(ex.getMessage());}

try{

con=DriverManager.getConnection("jdbc:postgresql://localhost/dbname","userna
me","");

st= con.createStatement();
}
catch(SQLException eft){System.err.println(eft.getMessage());}

//the error reported here is No Suitable Driver

try{

String stat="INSERT INTO ...."
System.err.println(stat);st.executeUpdate(stat);

}
catch(Exception e){System.err.println(e.getMessage());}
The Error reported here is Null Pointer Exception

Is there any thing special with the servlet trying to access the PostGresql
jdbc driver.