解决办法：php5.3开始后，废除了php中的”=&”符号，所以要想复制，直接使用 "=" 引用即可。

After hours of confusion and reading tons of posts I finally figured out that replacing PHP 4 style object creation, where new is assigned by reference:

$node_obj =& new someClass($somearg, $moreargs);

which in PHP 5.3.0 generates an E_STRICT message telling you that "Assigning the return value of new by reference is deprecated"

with the following, where & has been removed:

$node_obj = new someClass($somearg, $moreargs);

in some cases (at least in recursive loops while creating a tree of nodes containing child nodes) requires

unset($node_obj);

before the actual object assignment line to avoid all child nodes becoming identical.

Hope that delicate piece of information will save someone else a few hours.