Progressive download slide video not playing

Hi,

I two short courses comprising of 3 slides each, one which has a 80MB video to be viewed via progressive download.

In the first course the video is inserted as an event video, and plays fine.

However, in the second course I have had to add closed captioning and therefore the video is inserted as a slide video instead. In this course a curious and frustrating thing happens once it has been uploaded to an LMS. The first time the course is viewed, the video simply doesn't display. Captivate appears to start loading the video, but then the screen just goes blank as if the video has failed to load up. Yet if I close the course and then reopen it the video plays fine, along with the Closed Captioning.

The video is stored in the same folder as the course files, and as noted above is played via progressive download. The video is in FLV format.

I have tried this on two different LMS and encounter the same problem on both.

Thanks in advance for your help.