Specify more, like:
What type of movie file are you using? - examples: (avi, mov)
What codec are you using? (Uncompressed, DivX, DirectShow)
What are the dimensions? (NTSC: 720x480)
What is the filesize? (123 mb)
On what specific frame does it crash? Or as soon as you press "Render", does it crash?
If so, are there any effects on the first frame of the timeline? If there are any other objects on the first frame, does the rendering work if you disable them?
Not trying to overwhelm you, but collecting this information now will hopefully save time.