I would use print and not printNum.

1. Put each of you PDFs into a seperate movieclip.
2. Place the movies off the viewable area of the stage.
3. Give each of them a different instance name.

Code for buttons goes on a frame not on the buttons:

code:
myBtn1.onRelease = function(){
print(PDFHolder1, "bframe");
}

myBtn2.onRelease = function(){
print(PDFHolder2, "bframe");
}

myBtn3.onRelease = function(){
print(PDFHolder3, "bframe");
}



No need to feel stupid. Printing is tricky. I'm sure there are many more ways to accomplish this,including using a PrintJob, but this should work.