Save As based on Field Data

I have red through all the post concerning this and to be honest I am not much smarter than when I started.

I have tried to use the example posted by radzmar which I modifed as shown below but nothing happens:

I've placed the following in the directory:
C:\Adobe\Acrobat\8.0\JavaScripts

1. The folder level JS SaveAs.js

// Defining a trusted function
var mySaveDoc = app.trustedFunction(function(doc)
{
// Check current doc name
var aDocumentFileName = this.documentFileName;

// If-Statement for ensuring, that the save fuction is only done if PDF has exactly this name
if (aDocumentFileName == "Registration Form.pdf")
{
app.beginPriv();

// Save under Users documents
var myPath = app.getPath("user", "documents") + "/" + "Registration Form" + " - " + Part1 + " - " Part2 + " - " + Part3 + " - " + ".pdf";

doc.saveAs(myPath);
app.endPriv();
}
});

2. Added JS to the click event of a button:

//Defining variable(s) used for new filename
var Part1 = resolveNode("ReportForms.#pageSet[0].Att1.#area[0].txtCompanyname").rawValue;
var Part2 = resolveNode("ReportForms.#pageSet[0].Att1.#area[0].txtCompanyID").rawValue;
var Part3 = resolveNode("ReportForms.#pageSet[0].qrr_P1.#area[0].ReportDate").rawValue;
event.target.mySaveDoc(event.target);

Can anyone tell me what I am doing wrong?