- What is your build of DSSv6 lite you use? is it the latest.
- Did you try the same with the demo ( full version) or just the lite?
-Is this happened when you use the administrator( full permission user) to add/delete files, or the problem just only happened with a specific user account?
- Did you try this on many folders or just one folder? try to put folder with one file inside it ( different kind of files) and see if that work with you or not. and try to do that from different volumes too.

- Did you enabled the WORM on your volume?
With worm enabled on a volume, users cannot delete a file or folder, the entire volume has to be deleted. As there are no special rights for any users.
WORM= (Write Once, Read Many) .