Sometimes antivirus software gives false alarms over cracks files and keygens. It may happen because archives with keygens sometimes edit some system files. In 99.99% of cases cracks, patches and keygens are rather safe. Nevertheless you must look through antivirus scan report below and decide for yourself whether to proceed to download or not.
Discussion for Autodesk Inventor 2011 Keygen XFORCE-SiM crack.
As an alternative you can try to look for Autodesk Inventor 2011 Keygen XFORCE-SiM torrent file. You may need a little bit more time to download it but in fact bittorrents usually offer a full pack (software+crack) so you will not need to bother about product version match.