The transparency (as well as any other cool new technology) doesn't work in Netscape at all. Use Internet Explorer to be able to view transparent Flash Content.
For the transparency effect to work as desired, don't add a filler background element to your movies. Many developers add a large, white rectangular box, etc. to simulate white color. Make sure the drawing area behind the main movie is clear of any unwanted colors, etc. (it will show up in the final animation.)
I hope the above information helped. If you have any questions or comments regarding this
information or anything Flash related, please don't hesitate to contact me. I try to have all email inquiries replied to within 4-12 hours.
Philosopher, student, computer nerd who loves Computers, Books related to Computers, TV Shows about Computers, just your typical, average geek. (Looks at everything and wonders if it can be reproduced into a vector format and made into a Flash animation)