I've created a swf for a component live preview. The live preview appears to work ok when creating a new component, and setting the live preview in the component definition panel.
When I update an existing component definition (in a separate component library FLA) the live preview does not work.
The strange thing is if I copy the entire (component FLA) library and paste it into a new FLA it works fine (although in doing so I receive a whole bunch of errors in the output window saying - Plugin tool script error in method ik_isIKContainer).
Finally solved this issue. Hope this helps anyone who runs into the same problem.
There's an FLA dependent property which needs to be enabled - Control -> Enabled live preview