General Error When Using execDialog

I'm trying to create a dialog box form a mouse up action in a form, but the text that's entered in the box never appears in the assigned field.

Here is the code that I have in a separate file within C:\Program Files (x86)\Adobe\Acrobat 11.0\Acrobat\Javascripts

function trustedDialog(data){
  console.println("trustedDialog function");
  app.beginPriv();
  try {app.execDialog(data);}
  catch (e) {console.println("Trusted Dialog box exception is: " + e);}
  app.endPriv();
  return;
  };
  app.trustedFunction(trustedDialog);

Here is the code that I have for the mouse up event.

var oDlg = {
  strName: "", initialize: function(dialog) { 
     dialog.load({"usnm":this.strName}); },
        commit: function(dialog) { 
              var data = dialog.store();
              this.strName = data[ "usnm"];},
        description: { name: "KSA Input Box", elements: [
        { type: "view", elements: [
        { name: "Enter your text here:", type: "static_text", },
  { item_id: "usnm", type: "edit_text", char_width: 15, multiline: 1, height: 500, width: 500},
  { type: "ok_cancel", },
  ] },
  ] }
};
var f = this.getField("TextBody");
if( "ok" == trustedDialog(oDlg)) { 
    f.value = oDlg.strName; 
}

Whenever I run my code I'm getting this error in the console, and I haven't been able to figure out why.

Exception in line 35 of function trustedDialog, script Folder-Level:App:priveleges.js

Trusted Dialog box exception is: GeneralError: Operation failed.