Is this a site you've built yourself?
Why are you using query parameters?
I would suggest that you find a way to link directly to the file via HTTP.
Yes, I have created a site myself, My video located on various servers so sending correct url from database on that page for correct url.
OK. What might be happening here is that Captivate expects the URL to be in a particular format and it could be that the way your URL is structured is not compatible with what Captivate expects.
Take a look at this blog post from the Adobe blogs:http://blogs.adobe.com/captivate/2011/03/workaround-for-video-streaming-issues-in-captivat e.html
It might give you some pointers about the way that the URL needs to be set up.
I want to use progresive download for now, but this shows about streaming.