Hi Ricky,
Are you trying to open the PDF in a browser window, or downloading the PDF and opening it in Reader? If you're using a browser, which browser is it? You may need an updated plug-in. Please see Acrobat Help | Display PDF in browser | Acrobat, Reader XI
If you're trying to open the PDF in Reader, please make sure you have the most current version of Reader by chewing Help > Check for Updates.
Please let us know how it goes.
Best,
Sara