Cannot add/save page

Cannot add/save page

Hi,
I'm currently testing/learning Zoho Creator for a potential integration app.

I've defined several custom functions and I am trying to call one of them from a Page, like below (using the Script builder feature)
  1. <% someVar = thisapp.geopal.returnSomething(); %>
... but when saving, I constantly get the "Error at null" error message.

The custom function is simply
  1. string geopal.returnSomething()
  2. {
  3. return "sss";
  4. }
What happens in here?