Can NOT delete files on NAS White led 1.5TB - TWONKY Problem

I’m having similar problems with a World Edition II (2x1TB) system.  I can successfully copy files to folders in the Public share or a share that I’ve created separately through the web interface.  But after that, I cannot delete the files using the Snow Leopard finder.  I can only delete files through the terminal.

Any attempt to delete a file through the Finder yields an error message similar to the following:

The operation can’t be completed because the item “myfile.jpg” is in use.

Anybody else having this problem or know how to resolve it?  

-Aaron