Can't do the next question after video playing

We have created Questionnaire that contain the videos using Media Lab v2010 than imported the que file
to Experiment. When the Expriment file was running, the video played well. However after the video playing, there are still small black ractangle on the screen. I did right clik on it, serveral video functions appeared.
It didn't work to the next question. Is there any problem to the Media Lab v2010?
We need your help to fix that. Please let me know how we can do.