This is a problem encountered by many users and the Nova Development team released a fix that might overcome it.
Access the page and then read the steps you need to follow in order to fix the problem.
Official page: http://usa.novadevelopment.com/support/faq/prw/mpeg_error.htm
The first thing to do is to remove the compatibility tweak. Right click the executable file then go to Properties > Compatibility and uncheck the button. Launch the software again using Run as Administrator.