Which Adobe product are you trying to install? What operating system are you using? Finally which version of Internet Explorer are you utilizing?
Download the offline installers from http://helpx.adobe.com/content/help/en/flash-player/kb/installation-problems-flash-player- windows.html#main-pars_header and save them to disk, then close all browser windows and run the downloaded installers.
[topic moved to Flash Player forum]