Try to install FlexLabel.jar into 3.0 using "Install New JavaBean". It works in X2, but not in 3.0 (build 382). If you do FlexLabel5.jar, it will work correctly. There are small changes in the ma
nifest and how the jar was packaged.
Related but different from bug #3648.
If you need the source files for these jars, they are at http://developer.java.sun.com/developer/onlineTraining/Beans/JBeansAPI/Magercises/index.html