how to export movie as video?

I did this a couple of years ago and now can't seem to get it to work.
I followed all of the instructions in the help section and the "saving" window pops up for about 2 seconds and goes away and of course does not save. I am using TW4 Pro. I tried selecting all the different formats but none work.
Any suggestions?

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Nikon D300, D3s, Nikon 10.5 lens, RingT105N+Footplate+MrotatorTCPs, Giottos MT9261 Tripod, Manfrotto 410 Jr geared head.

If you know the "secret" then everyday is a good day!

Thought I would bump this back up. I'm still looking for the solution to the problem. I'm using TW5 pro now. It was suggested to download this codec http://www.free-codecs.com/download/ffdshow.htm but it does not seem to help either.
Thanks

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Nikon D300, D3s, Nikon 10.5 lens, RingT105N+Footplate+MrotatorTCPs, Giottos MT9261 Tripod, Manfrotto 410 Jr geared head.

If you know the "secret" then everyday is a good day!