In trying to learn ActionScript in FlashBuilder, I ran across a Library that needs to be added to my project. The code is at http://www.rightactionscript.com/ascb (the ascb.display package). I have tried placing it in several directories on my hard drive and setting the build path to those directories (Projects -> Properties -> ActionScript Build Path), but get an error (non-verbose, i.e. no explanation) on attempting to run the code. Within FlashBuilder, the classes show up in the Package Explorer, and the code completion works fine....what am I missing?