This is a symptom of a problem with the Adobe plug-in for MS-Internet Explorer.  To resolve this make sure you have the latest version of Internet Explorer Installed, download and install a current copy of the Adobe Acrobat Reader.

1.) Install MS Internet Explorer 7, or a later version of IE if an earlier version of IE is installed. If this resolves the problem, you can ignore the remaining steps.

2.) Reinstall the latest version of Adobe Acrobat Reader with Administrator login. The download link at the Adobe website for the Adobe reader is as follows:

http://ardownload.adobe.com/pub/adobe/reader/win/8.x/8.1/enu/AdbeRdr810_en_US.exe

Please see the topic File does not begin with %pdf for instructions on how to configure your PDF file opening options if you also have the Full Adobe Acrobat (not just the reader) on your system.