Cannot get Javascript to populate form fields.

I am very new at working with Javascript. I am attempting to reverse enginer a script that populates form fields in a seperate document when it opens. The scrpt is triggered using a button. The form opens without ant problems. Below is the script. It is also possible that there is a formatting issue with the PDF forms.

I am working with Adobe 8 Pro.

var a = this.getField("Mug").value;

var b = this.getField("Key").value;

var c = this.getField("AgncCas").value;

var d = this.getField("Mfirstname").value;

var e = this.getField("Mlastname").value;

var suppDoc= app.openDoc("supp.pdf", this);

suppDoc.getField("Mug").value=a;

suppDoc.getField("Key").value=b;

suppDoc.getField("AgncCas").value=c;

suppDoc.getField("Mfirstname").value=d;

suppDoc.getField("Mlastname").value=e;

suppDoc.getField("Mug").setFocus();

suppDoc.getField("Key").setFocus();

suppDoc.getField("AgncCas").setFocus();

suppDoc.getField("Mfirstname").setFocus();

suppDoc.getField("Mlastname").setFocus();

Any suggestions would be greatly appreciated.