I just read a nice article of Alex Harui about how to properly work with modules to prevent memory leaks especially when unloading. He descripbes pissible reasons and ways how to avoid pproblems.
Please read full text here - http://blogs.adobe.com/aharui/2009/08/what_we_know_about_unloading_m.htm... Another articles on same problem - http://blogs.adobe.com/aharui/2009/05/more_on_finding_memory_leaks.html
