If you choose to "View Output" after publishing your file, you will be using the file-system path (on Windows, something like: file:///D:/Your Project/yourpresentation.htm) to the content, and even if the files were published directly to a web server over a LAN, you are not actually viewing it through the web.

Here's Adobe's explanation of how the security for local content works:

When Flash Player runs, it performs two main checks before playing the content. If the content doesn't pass these checks, the content is stopped and cannot perform any further action...

During the first check, Flash Player determines whether the content is running locally or on the Internet. If the content is on a website, there is no risk because it is running within a framework that prevents access to your information or local data. If the content is on your local computer or network, Flash Player proceeds to the second check.

During the second check, Flash Player determines if this content is trusted for local playback by checking a list of trusted content stored on your computer. Trusted content is allowed to proceed; content that is not trusted presents a potential risk and is stopped...