Can not call node_load() in Value code

I input such code in the Value code textbox:

$node = node_load($row->edit_node);//I use dpm($row) first and find the edit_node is the nid.
dpm($node);

But no dpm output at all!

And you can see from the screeshot there is no $data in the AVAILABLE VARIABLES area which exists in the 7.x-1.0-alpha1 version.

Or, the problem is that node_load function can not called in the Value code?

BTW, in the "Enable click sort" section, are the Views PHP field rows sorted by the Views PHP field Value code other than the Output code?