Cannot Copy to a shared Hard Drive - com.apple.desktopservices

I have a Mac Mini with 10.6.4 that is working fine (except for this problem)
The Mini is on my network, and has one factory internal drive, and two external drives that I use for storage of images, and software originals.

After mounting the drives over the network, whenever I try to copy any file to any of those drives from my MacBook Pro 10.6.4, here is what happens.

(Oh yes. … Both machines versions of 10.6.4 are fully up to date. After reading other suggestions, I updated both machines via the 10.6.4 combo update this morning, and the same problem still happens)

First.) I log in over the network as the owner of the Mini machine, from the MBPro also as Owner.
Second.) I can choose, any drive, or all drives, including the internal drive, on the Mini.
Third.) The chosen drives seem to mount normally on the desktop of my accessing machine, MBPro.
Fourth.) I can copy from any of the mounted drives to my local machine without problems.

Now comes the problem.

Fifth.) I try to drag any file or folder to any of the mounted drives.
Sixth.) I am asked by (Details - com.apple.desktopservices) to, "Type your password to allow Finder to make changes."
Seventh.) I answer the request with my name and password, and hit return.
Eighth.) I get the error "The operation can’t be completed because an item with the name “” already exists." ()
Ninth.) There has been created a 0k sized file on the target drive.
Tenth.)