I was taking the flex in a week tutorial and it mentioned that it uses shared libraries, and the user would have to go online to get the library for an action script. So what if a user does not have an internet connection? How can you embed the library into the swf so the user does not have to go online to get the library if they already don't have it on their computer?
In Project > Properties under Flex Build Path, there is a dropdown box at the top that says Framework Linkage. If it says "runtime shared library" then it will be shared libraries. You can change it to "merged into code" and then everything you need will be put in one SWF as opposed to requiring the runtime shared libraries.
Hope that helps!