I am trying to take advantage of shared libraries and am having a problem with shared button symbols. Although I can specify an event (ie: on(release)] for the button, when the movie plays, the event never fires. As soon as I convert the button from a shared symbol to a resident symbol, the scripting works fine.
I have run through a number of debugging steps pertaining to Flash and my operating system (WinNT) and have not been successful in fixing this problem.
You are trying to attach an action to the shared instance, which is just a placeholder and not a true symbol.
I don't think the logic behind this is very clearly explained in the documentation, but this tech note relating to shared symbols has the solution:
"Sharing actions: Actions are attached to instances of symbols, but only symbols themselves can be shared. To share button or movie clip (onclipEvent) actions you need to "nest" an instance of the symbol to which the actions attached inside another "container" movie clip. The container symbol can then exported as a shared asset and the actions will work as expected."