Try running the application as Administrator and then make sure you're not using other applications to open the file. Close all of them and then load the file. A strange behavior was encountered on my computer when I loaded the file. The software began looking for the Fonts files. However, I let it scan and the file opened without errors. This could be a cause to the opening issue. Open or Play a file and let the application alone for a 1-2 minutes. It might be doing some initial scan and if you try to use other functions while it's scanning, then errors might appear.
The developers provide users a comprehensive FAQ section on their website. You can use that section to learn how to overcome possible issues with their applications.
FAQ page: http://www.any-video-converter.com/support/faqs/