Welcome to Adobe Forums.
Download offline installer for Adobe Flash Player from here : http://helpx.adobe.com/flash-player/kb/installation-problems-flash-player-windows.html#mai n-pars_header
Download and save the Flash Player uninstaller
Download the Adobe Flash Player installer(s) directly by right clicking one (or both) of the following links and selecting "Save Target as" (using IE) or "Save Link as"(using other browsers).
If you use other browsers I recommend downloading BOTH - Save them to your downloads folder and DO NOT run them yet.
Close your browser and check the Task Manager to be sure it's closed completely.
Run the uninstaller.
Reboot your system.
BEFORE you open anything else, locate and run the installers. Your Flash Player should be updated for IE and other browsers.
If you still have troubles with IE, see: Enabling Flash Player in Internet Explorer
Do you have any idea why so many people are getting these script errors these days?
Not sure, as this seems to be coming on download and not reproducible at my end (Tried on mulitple computers)
Possibly this is an issue with official Network restrictions on user's computer.
Found it in some other topic; it seems to happen if the language setting on the Adobe.com website is set to somthing other than English (e.g. some Eastern European languages). Changing it to English will allow the download.