Returning object name from function and accessing properties/methods

Hello,

This should be simple but so far I am striking out. I have a function that will search the current form for a button that I pass in as a variable:

function FindBtn(BtnName) // Pass in Name of Control
{
  var btn,p;
  p = Sys.Process("M3.AKShell");
  var PropName = "Name"; // Reference the control's Name property
  var PropValue = BtnName; // The Name property value for the control
  btn = p.findChild(PropName,"WinFormsObject(" + PropValue + ")",200000,true); // Look for the button on the current form
  if (btn.exists)
    {
    Log.Message(btn.Name + " was successfully found");
    return btn.FullName;
    }
  else
    {
    Log.Error("The " + BtnName + " button was not found");
    }
}

This seems to work well. I can follow along and see that it finds the control I am looking for. I am then trying to call the button's ClickButton event, which is not working. No error is returned, the log shows the steps as passing. Here is my calling function:

function clickContactTab()
{
  var VndrBtn;
  VndrBtn = FindBtn(APContactTab);
  VndrBtn["ClickButton"]();//<--This line is not working
}

I can see that the FullName is returned to the calling function, however, I am receiving the error:

Object doesn't support this property or method


and the button is never actually clicked. What am I missing?