acroforms saveas

I placed this code into acroforms to create and save a document in the mydocs folder. It won't work? Why?
I am new to javascripting. I got this script from the Javascript for acrobat reference API.
 
var myDoc = app.newDoc();
var myPath = app.getPath("user", "documents") + "/myDoc.pdf"
myDoc.saveAs(myPath);
myDoc.closeDoc();