Thanks for posting here and telling us your problem.
Are you sure you are using the latest version 220.127.116.11? If so, please kindly take the following steps to send us bug report so that we can check and get a solution for you.
1) Add your wmv video file to the Mac Video Converter, right-click the added file to go to "Bug Reporter".
2) Then click "Report" and the /var/tmp folder will display, from where please find the "leawo-dbg.dmp" file and send it to us at email@example.com
Thank you in advance for your cooperation.