Thank you for taking the time to write to us, but this is not
a bug. Please double-check the documentation available at
http://www.php.net/manual/ and the instructions on how to report
a bug at http://bugs.php.net/how-to-report.php

$name will be used as the class name to be instanciated.

When using ZE2, this will indeed result in a parse error. 
When using ZE1, it works and the property name will be used as the class name to be instanciated.

et@edea:~$ /usr/local/sources/php-4.3.1/sapi/cli/php
<?php
class Foo {
  var $bar = 'Foo';
}
$foo1 = new Foo;
$foo2 = new $foo1->bar;
?>         
         
et@edea:~$ /usr/local/sources/unstable/php5-200305031330/sapi/cli/php
<?php
class Foo {
  var $bar = 'Foo';
}
$foo1 = new Foo;
$foo2 = new $foo1->bar;

Parse error: parse error in - on line 6

But i think this is the way it should be, because it looks ambiguous when you see new $object1->name($arg); - on the first look, it looks like a call to the method `name' and not like passing arguments to a constructor. Somehow, it's the same for the new $name() - it could be mistaken as a dynamic function call. Maybe there should be a function to instantiate objects dynamically? 
Like object create_instance(string classname[, mixed constructor_args...])