How about this?
http://www.youtube.com/watch?v=DcrpVMEyS1w
or if still troubles, this:
http://help.adobe.com/en_US/captivate/cp/using/WS5b3ccc516d4fbf351e63e 3d119e9582a67-7fe5.html
Match your FPS - why set one portion to 30 and another to 15? I'm not even sure how you're managing to do that 
One more that may help:
http://blogs.adobe.com/captivate/2012/06/hd-videos-within-a-regular-ad obe-captivate-project.html
-E