Why is Camstudio video annotation not working?

I installed camstudio but video annotation is not working, just te black screen even after all the settings. please help
thanks

"Video Annotations" is essentially a picture-in-a-picture feature. There is a lot going on inside your box to make that happen. Cam Studio is taking the input from your web cam and super imposing it over the display output and recording it real-time.

Due to different operating systems and different web cam drivers, there have been a number of problems and few solutions for them. See if you read anything in the support forum on the subject that might offer some help:

http://camstudio.org/forum/comments.php?DiscussionID=2