are you installing from a dvd?
if yes, trial downloading the trial and using your serial to activate. the adobe link is: http://www.adobe.com/cfusion/tdrc/index.cfm?product=flash
and the link for a direct download is: http://prodesigntools.com/adobe-cs6-direct-download-links.html
to use the latter, you must follow all 7 steps (esp, steps 1-3) or you'll have a problem.