Good onya for posting Jeanette. Personally I believe it's especially important for astrophotographers who are just cutting their teeth to post. It encourages others and it give you a place to gauge your own improvement over time. On our own computers it's tempting to delete those earlier non-award winning attempts
but here they can stay for posterity.
If you are having trouble with Registax choking on the Avi, run it through Virtual Dub and save it as individual bmps. Then select all the bmps in Windows explorer and drag and drop them into the Registax window.
should work a treat.