What steps will reproduce the problem? 1. Connecting to any SFTP server 2. Exception is thrown.

There are a couple of problems here.

1. MetalVFSFileChooserUI incorrectly calls getCurrentDirectory() instead of getCurrentDirectoryObject. Related to your File/FileObject changes.
2. This now works correctly, unless you add a path to the ConnectionDialog. This is corrected by setting the setUserDirIsRoot configuration to false. Must be a change in commons-vfs2 behavior. Empty path still works fine.
3. Unrelated misspellings in code (purely cosmetic)

I can't figure out how to create a patch from hg so I've attached the output of a "hg diff". I'd appreciate it if you could patch and release a new version in the near future. I've cloned a copy for our internal purposes, which will do for the interim. Thanks!!

Rajin