Hi there. Like you guys, I experienced this problem and redownloaded many times. Finally, I have found a solution and it may work for you. This is in regards to the 2013 version, however, it may work for you.
When the download has finished, turn off your anti virus scanning shields. Make sure it is not actively scanning any files.
Right click on your setup file and click RUN AS ADMINISTRATOR. When asked if you want to do so, click YES.
The extraction should take place without any issues and following that the install process.
Hope this works for you.
Regards,
Trev.
Problems downloading the Autodesk software and/or CRC errors may be avoided by using another web browser, or using the alternate browser download method.
For more detailed information on this process, please see the following blog post tip here:
http://upandready.typepad.com/up_and_ready/2011/08/downloading-software-browser-download-vs-download...