I have a slide containing a .jpg.  The .jpg file is a screen shot of text.  
Since I'd like users to be able to click on some of the words on the .jpg and
open another PPT file, I added rectangle shapes on top of the .jpg.  The
shapes have no fill and no line.  I added a hyperlink to the shape.  

On a PC with PPT, users can click anywhere on the rectangles and the
hyperlinked files open perfectly.  However, I put the presentation, along
with the hyperlink presentations, on a system that only has viewer.  When
viewing the slide show in viewer, users must click on the border of the
rectangle to get the hyperlinked file to open, instead of anywhere on the
rectangle.  If I fill the rectangle in, they can click anywhere.  I need the
rectangle not to have a fill though, since I need them to be able to see the
text on the .jpg file behind it.  Any idea why this wouldn't be working?  
Thanks.