When publishing a Flash movie you can turn off the right-click menu, however this would not stop someone from downloading the SWF and fast-forwarding, etc, manually.

More importantly, if you open your Flash file with a text editor you will see the password there in plain site. There are also Flash decompilers which take apart swf files in a controlled manner and bypass password protection.

Quite simply, you can not protect content held in a SWF file. If you have important information then store it server-side and setup a basic authentiction system between Flash and the server. That is the only fullproof way.

If you want to keep your current setup you could create a function that checks the frame number and prevents certain frames from being viewed if the password has not been entered, but this would not stop a Flash decompiler, or someone simply opening up the SWF in a text editor and reading the content.