reg:"Driver Not found-error"- need u r suggestions

hello sir,

    When I am trying to connect my pgsql with jdbc, getConnection throws the exception "Driver not found for the URL jdbc:postgresql:testdb".
   I am using the jdk 1.3.1 and my code goes like this
     'Class.forName("org.postgresql.Driver");
     Connection con =       DriverManager.getConnection("jdbc:postgresql:testdb","root","passwd");
     here
       "testdb"  refers to database name,       
       "root" refers to username  and
       "passwd" refers to userpassword.
      I had tried with these following jdbc drivers                     pg72jdbc1.jar,pg73jdbc2.jar,pg72jdbc2.jar  from 
     postgresql.org (postgresql jdbc downloads.htm).I had tried each one of these drivers by setting one in the classpath.
      I hope u can help me to fix this error.
                               thankyou.
with regards:
Rajesh Kumar.