John, I feel your pain and agree that popping up a simple warning type of
error messages in front of 300 people I am presenting to is a crime.  The
pop-up error message completely discredits the presenter, ruins any
continuity, and looks amateur.  I would understand if the program crashed,
or an actual virus was found, but not when I built the presentation to show
on my computer with hyperlinks I inserted.  ARgh!  Don't get me started on a
rant...

((Deep breath))

OK, now what do you do about it.  Check out
http://www.pptfaq.com/FAQ00406.htm

Download and run the disable prog here. It will ONLY work on your computer
though , it doesn't follow the presentation

http://officeone.mvps.org/download/hyperlink_warning.html

I also discovered by accident that if you package your file for CD using the
folder option you dont get the warning as long as you use the full programme
to run it (not the viewer). I havent tested this carefully and with an html
file you might get missing links if you dont also move dependant files.