How to add my custom components in netbeans pallete

when I design a custom jframe form in netbeans.it may be a simple button or a complex calculater.Then if I want to add these custom components in netbeans pallete so that
I can reuse it in any jframe by just drag and drop.when I select my custom jframe from project window and right click and  goto 'tools' and then 'add to pallete',this jframe is added in pallete.but when and try to drag and drop it on my any jframe it gives following error.

cannot load component class practice(project name).calculater from project e:\wdd\idework\practice.
the class could not be found.note that class must be compiled and must be the part of sources or dependencies of the project
where the target GUI belongs to.

note that my custom component which I want to add in pallete is compiled and run and I am trying to drag ang drop it on another jframe of the same project.
kindly guide me what is proper way of adding custom components made in netbeans in its pallete to reuse it again and again.
regards