Hi Jeff,
One possible suggestion is that you may have saved the panel in the embedded library within the original project.
You need to open the old project, extract the panel to a folder, then load that folder using the library manager in the new file. The panel should then be available for use. This thread
here may be useful for instructions.
If it isn't in the embedded library, it may just be in the project specific library rather than the general shared library. Move it to the shared library then reload your libraries within ArchiCAD.
Hope that helps.