class Payment {
   var  $MyVar;

   function DoNothing () {
   }
}

class Report {
   var Payments         // Payment Object

  function Report () {
     // Initialize payments object
     Payments = new Payment;
  }
}

Script on Page 1:
     session_start();

     $Report = new Report;
     // Report now contains instance of Payment object 

     session_register(Report);

     $Report->Payments->DoNothing();   // Call ANY function

     header("Location: ../Php/Page2.php");

Script on Page 2:
     session_start();
     
     echo $Report->Payments;   // This says that Payments is a non-object.
     // Any non-object members of $Report are OK.  Only child objects seem to be affected.

If function call to $Report->Payments->DoNothing() is removed from page 1 then things work OK

Our same code under 4.0.1pl2 works fine.  We noticed the problem only when we upgraded to 4.0.3pl1