It sounds like possibly a graphics issue with 2.5 and DirectX. If you are using an integrated graphics card that could be the problem.
The best thing to do is contact Support using the support from and give them all the information they require regarding your system setup and DirectX log. Details about this can be found from the link below.
http://www.reallusion.com/CustomerSupport/User/QForm.aspx
I hope you get a fix for this soon.
Peter EdwardsForum Moderator
iClone Daily Blog