The forums (www.were-here.com) and Flashcoders (www.figleaf.com) are valuable resources for finding answers to those problems that are not on the macromedia site.
Documentation includes written instructions for all members of the crew, it is indispensable for training production artists, animators, flash technicians, and programmers that are new to the project.
For programmers, you should comment all script in your flash movies if it is extensive and will be used a great deal in the future. It is also useful for yourself if you want to remember what a section of your programming relates to in your movie to reuse the script in another project.