Custom RH9 WebHelp skin: Problem opening PDF file from custom button

Hi, I've been troubleshooting and checking forums trying to figure out how to get a PDF file to open from a custom button on my WebHelp skin. It worked for me once upon a time, but I changed something in the document and tried to upload the new version and it has errored out ever since.

I want to have the ability to open the PDF in a new window from the custom button (called 'Printable PDF' on my skin), so I am using the following custom JavaScript in the 'Click On' field of the the custom button's components: window.open('print_test.pdf','printWindow','menubar=0,resizable=0,width=900,height=500,scrollbars=1');  I know the script is good because I have the same script for the Support custom button and it works great. The only difference between those scripts is the Support script calls an .html file instead of a PDF and the window names says 'supportWindow' instead of 'printWindow'.

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I've tried deleting and recreating the custom button, changing the JavaScript with a developer's help, generating the help on another machine thinking it was a glitch with my browser (using IE8) or RoboHelp license, and combing the help files numerous times. I've also ensured that the PDF file is stored in the skin and project folders along with the other project files/folders. I've used previous versions of RoboHelp and had no problems attaching a Word document and PDF, so I'm wondering if this is a bug in RH9?? Especially since it worked for me initially. Any assistance and/or fresh ideas are welcomed! Thank you!