OS X and Acrobat contain two sources of confusion when trying to view PDFs with Sarafi.
First you must be sure that you are viewing PDFs with Adobe Acrobat and not the built-in "PDF Viewer" made by Apple. See OS X issue.
Second, Safari does not always show PDFs properly depending on your combination of OS X and Safari versions. If you’ve already upgraded to the latest release of Acrobat Reader, issue one above has been resolved, and the PDFs still do not display properly, try viewing your reports in Internet Explorer. The long term fix is for Acrobat Reader and its browser plug-in to be debugged by Adobe Systems, the creators of Adobe Acrobat Reader.
Support document 275