Make sure to use the latest version of Adobe Reader. You can download at: http://www.adobe.com/products/acrobat/readstep2.html

Or get the latest updates available for your version of Adobe® Reader at: http://www.adobe.com/downloads/

More support regarding Top Issues available on the Adobe site at: http://www.adobe.com/support/products/acrreader.html

It's usually best to save the file to your hard drive rather than just open it in your browser.