I think when you install a new version of B4J, you get a new Libraries folder with it, so any jar you added to it for the previous version will be missing on the new version.
I put my jna jars in my extralibs folder, so even when I upgrade B4J they are still available.
sure, my mistake. In library folder was not two libraries. After copy old library folder to the new version is everything OK!!!
It was too late in the night maybe - I never seen jar library - I overlook...