Can you advise of the hardware and software you are using to achieve this. Coupel of things worth checking,

1. Make sure that your export video is DV Type 1 (Assuming that your camera is same - most are).

2. Exporting a video to DV Camera is a system intensive thing. Your system will use a lot of resources and temporary files for this. If you have the option in your software to set your temp files to a dedicated video drive then do this.

3. Because export to DV is system intensive, then it is necessary (Particularly if you only have one drive) to keep your hard drive defragged.

Hope that helps a little.