this report has been filed here:

https://bugs.edge.launchpad.net/ubuntu/+source/nautilus/+bug/316653

log: http://launchpadlibrarian.net/25701119/gvfs-log.txt

"To reproduce this bug, open some samba share 'smb://myserver/myshare', for example, with nautilus. Create a deletable FILE named 'mytest', for example, with any contents in 'smb://myserver/myshare'. Now, create a FOLDER also named 'mytest' in the same place 'smb://myserver/myshare'. When the FOLDER 'mytest' is created, the FILE 'mytest' is deleted without any prompt. (you must have the privileges to create/delete folders/files in the share and the FILE attribute of 'mytest' must be writable)

The file system won't allow a file and a folder both with the same name coexist in the same place, but I expect nautilus should at least prompt before it deletes the file. I have tested it on my two different machines and both have the same issue."

"

1. boot up from livecd which is created from 'ubuntu-9.04-rc-desktop-i386.iso'.
2. run nautilus and go to directory /tmp by input '/tmp' in the location text box in nautilus window.
3. create a folder 'myshare' in /tmp.
4. right click on 'myshare' and select 'Properties'.
5. go to the tab 'Share' in 'myshare Properties' pop up dialog.
6. check the option 'Share this folder'. when the option is checked, a dialog 'Sharing service is not installed' will appear. click on the 'install service' button in the dialog and it will start to download and install 'samba' package.
7. when the installation is done, a dialog prompting you to 'Restart your session' appears. click on the 'Restart session' button in the dialog to restart the session. however, the session is not restarted after the button is clicked. i need do it by myself manually.
8. run 'gnome-terminal' and execute

    sudo kill -term `pgrep '^Xorg$'`

   to restart the session manually. The login screen will show. wait until timeout in order to login as user 'ubuntu' automatically.
9. run nautilus and go to /tmp.
10. right click on 'myshare', select 'Properties' and go to the 'Share' tab in the dialog.
11. check options 'Share this folder', 'Allow other people to write in this folder' and 'Guest access (for people without a user account)' in the 'Share' tab and click on 'Create Share' button to apply the change.
12. after the 'Create Share' button is clicked, a dialog 'Nautilus needs to add some permissions to your folder "myshare" in order to share it' appears. click on the 'Add the permissions automatically' button to add the permissions.
13. open another nautilus window and input 'smb://localhost/myshare' in the location text box in nautilus window.
14. create a FILE 'mytest' in smb://localhost/myshare (select 'File -> Create Document -> Empty File' from the menu bar of the nautilus window and rename the file to 'mytest').
15. create a FOLDER 'mytest' in smb://localhost/myshare (select 'File -> Create Folder' from the menu bar of the nautilus window and rename the folder to 'mytest'). When the FOLDER 'mytest' is created, the FILE 'mytest' is deleted without a prompt.
"