Q:

Export in slave notebook

I have a very complicated analysis running on a notebook named Called_notebook.nb which depends on two parameters. To automate the process, I call this notebook in a loop from a master notebook, like this:
Monitor[

 Do[
    Do[

        linked`i = i;
        linked`j = j;
        NotebookEvaluate[NotebookDirectory[] <> "Called_notebook.nb"],      

     {j, 10}],
 {i, 27}],

 {i, j}]

The problem is that the Called_notebook.nb is supposed to export figures to .png files, which does not happen within this approach (that is, the export command works when I run the slave notebook by itself but does not - no file appears - when I run it from the master notebook). I also tried to move the Export command to the master notebook, below the NotebookEvaluate, but then I get an error within the loop. 
How can I solve this?

A:

Use UsingFrontEnd e.g.
UsingFrontEnd[NotebookEvaluate[NotebookDirectory[] <> "Called_notebook.nb"]]

and possibly
UsingFrontEnd[Do ...
  NotebookEvaluate[NotebookDirectory[] <> "Called_notebook.nb"]]
 ...]

also mentioned here

