The problem was detected in NB 6.0 and 6.0.1. In short beansbinding doesn't work in NB Modules. It works perfectly well 
in standard java applications but not inside an NB module. I've tried in NB 6.0 and 6.0.1 and in a fresh installation 
of NB 6.0 in a second computer to eliminate possibility of problems with my computer installation.
 
The apparent problem can be reproduced like this:
In an NB module, create a new form by creating new Window component. Create also a simple bean with only one field, 
compile the class and register it as a binding source by drag and drop it inside the form. Insert a single text field 
from the palette, by pressing the right button over it select bind->text, chose the bean from the first combo and the 
field from the second. 
 
So far, so good. Unfortunately an error appears in the form's auto-generated code in the line "private 
org.jdesktop.beansbinding.BindingGroup bindingGroup" and the error is "package org.jdesktop.beansbinding does not 
exist". This line is in the protected area so I can´t correct it even if I knew how. If I do ctrl-space in front of 
org.jdesktop. the only member that appear is "layout" not the ones that should 
appear "beansbinding","swingbinding","el" or "observablecollections".

Following a sugestion from a user in dev@openide.netbeans.org I've packaged beansbinding-1.2.1.jar into a library 
wrapper module but the problem persisted.