Noticed in log file:
INFO [org.netbeans.modules.netbinox]: Install area set to file:///vboxsvr/space/src/nb/main/nbbuild/netbeans/
Clearly this is wrong; File.toURI would have given file:////vboxsvr/space/src/nb/main/nbbuild/netbeans/ and Path.toUri would have given file://vboxsvr/space/src/nb/main/nbbuild/netbeans/, but file:///vboxsvr/space/src/nb/main/nbbuild/netbeans/ corresponds to a nonexistent folder C:\vboxsvr\space\src\nb\main\nbbuild\netbeans.
Not sure what the practical impact would be, but consider whether NetbinoxFactory.toFileURL should be written differently.
Looks like the practical impact is not huge.