Are you using Windows 7 with Intel graphics? If so please refer to the link below which contains important information on this problem.
https://forum.reallusion.com/Topic34890-21-1.aspx
If you are using a different combination of OS and graphics chipset then first try updating your graphics drivers. This often resolves issues like those you are experiencing.
If you are unable to resolve the problem, please contact Reallusion Support using the link below for further assistance. They should be able to help you fix this issue.
http://www.reallusion.com/CustomerSupport/User/QForm.aspx
Thanks.
Peter
Forum Administrator
www.reallusion.com