Hi Felix, I think I spotted the issue. The 'exports' file is missing from the knopflerfish jar. In the previous version it was included in the upstream tarball and the code to regenerate it was disabled by 30_fix_jar_build.patch. In the latest version the exports file is no longer in the tarball. I enabled the build of the Ant task, this allowed me to remove the patch and now the exports file is properly generated.
Could you try building knopflerfish-osgi from the current HEAD of the Git repository and test again with freeplane please? If it works well I'll upload the update. Emmanuel Bourg