If you have purchased a PDF product that won't open correctly, you may just need to upgrade your Adobe Reader. We suggest you completely uninstall your current version and then download and install the newest version as a new install. You can get the newest version here - Adobe Reader Download http://www.adobe.com/products/acrobat/readstep2.html. Uninstalling any older versions and installing the newest version should allow you to open the file.
If that doesn't work you may want to try downloading again just to make sure you didn't get a corrupt download. If neither of these work please let us know your order number and the title of the product and we can look for another solution.