Custom Save button (JScript) not working

I am trying to add a custom save button at the end of my forms. The code is
as follows:

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function XDocument::OnSaveRequest(eventObj)
{
var header = "file:///";
var drive = "C:/";
var mainFolder = "Electronic%20Forms/Completed%20Forms/";

XDocument.UI.Alert("at 1"); // Debug code

var filePath = header + drive + mainFolder;
var fileName = "test.xml";
var fileURL = filePath + fileName;

XDocument.UI.SetSaveAsDialogLocation(filePath);
XDocument.UI.SetSaveAsDialogFileName(fileName);

XDocument.UI.Alert(fileURL); // debug code

eventObj.IsCancelled = eventObj.PerformSaveOperation();

if (eventObj.IsCancelled)
{
XDocument.UI.Alert("Save Cancelled");
}

eventObj.ReturnStatus = true;

XDocument.UI.Alert("Form saved.");

}

function CTRL85_5::OnClick(eventObj)
{
XDocument.Save();
}
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If I save the form using the save command on the toolbar or File menu, the
SaveAs dialog box appears with the correct file path and file name. However,
when I call the XDocument.Save() command in the OnClick() event handler of
the button I get the following error message:

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The following error occurred:

InfoPath cannot save the form.
The OnSaveRequest function returned a value indicating that the save failed.
The following error occurred:

The form does not have a file name.
File:script.js
Line:71



File:script.js
Line:90

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