That bug has been described on https://launchpad.net/distros/ubuntu/+source/nautilus/+bug/45382

"Open a remote folder via SSH with nautilus.

Open another remote folder.

Drag and drop a file from one remote folder to the other.

Get a "generic error". Screenshot to be attached.
...
http://librarian.launchpad.net/2724232/Screenshot.jpg
Screenshot,jpg

Screenshot of the error message.
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> Does gnomevfs-mv works fine for that?

Okay, I just tried several things. These all work okay:
 - gnomevfs-copy /
     ssh://cwagner@server/path/to/dir/briefcase.tmpl /
     ssh://cwagner@server/path/to/dir/survey.tmpl
 - gnomevfs-copy /
     ssh://cwagner@server/path/to/dir/survey.tmpl /
     ssh://cwagner@server/path/to/dir/survey.tmpl.bak
 - via Nautilus, moving *or* copying the file to *another directory*.
For example, if I am sitting in ssh://cwagner@server/path/to/dir/ and
select file.tmpl and hit Ctrl+C, then move up a directory to
ssh://cwagner@server/path/to/ and paste by hitting Ctrl+V, all works
okay. I can even *re-paste* over the file and I get a reasonable dialog
warning me: "A file named "groups.tmpl" already exists. Do you want to
replace it?"

So, in my case, the problem seems to only occur when trying to copy a
file and paste a copy back into the same directory in which the original
exists. What do I expect to happen? I expect to get a copy of the file
with a new name (e.g., "my-file.txt (Copy)") as happens when copying a
file, using the same technique, within a local directory.
..."