VirtualBox: issue with symlinks in shared folders

Some time ago there was a thread to exact the same problem: Can't create symlinks in virtualbox shared folders. Now it's closed (why?). So I start a new one, because I've got this issue now and cannot find a solution.

Short issue description: By attepms to create/place a symlink in a shared folder an error occurs:

root@devmv:/var/www/sandbox/zf1sandbox# ln -s /lib/ZendFramework/ZF1 ZF1
ln: creating symbolic link `ZF1': Protocol error

I've already tried to activate the symlinks for my shared folder "workspace" in different ways:

C:\Windows\system32>VBoxManage setextradata "Dev VM" VBoxInternal2/SharedFoldersEnableSymlinksCreate/var/www 1
C:\Windows\system32>VBoxManage setextradata "Dev VM" VBoxInternal2/SharedFoldersEnableSymlinksCreate/var/www/ 1
C:\Windows\system32>VBoxManage setextradata "Dev VM" VBoxInternal2/SharedFoldersEnableSymlinksCreate/workspace 1
C:\Windows\system32>VBoxManage setextradata "Dev VM" VBoxInternal2/SharedFoldersEnableSymlinksCreate/workspace/ 1
C:\Windows\system32>VBoxManage setextradata "Dev VM" VBoxInternal2/SharedFoldersEnableSymlinksCreate/M:\workspace 1
C:\Windows\system32>VBoxManage setextradata "Dev VM" VBoxInternal2/SharedFoldersEnableSymlinksCreate/M:\workspace\ 1

I don't get errors like

C:\Windows\system32>VBoxManage setextradata devvm VBoxInternal2/SharedFoldersEnableSymlinksCreate/workspace 1
VBoxManage.exe: error: Failed to create the VirtualBox object!
VBoxManage.exe: error: Code CO_E_SERVER_EXEC_FAILURE (0x80080005) - Server execution failed (extended info not available)
VBoxManage.exe: error: Most likely, the VirtualBox COM server is not running or failed to start.
C:\Windows\system32>VBoxManage setextradata "Dev VM" VBoxInternal2/SharedFoldersEnableSymlinksCreate/workspace 1
VBoxManage.exe: error: Failed to create the VirtualBox object!
VBoxManage.exe: error: Code CO_E_SERVER_EXEC_FAILURE (0x80080005) - Server execution failed (extended info not available)
VBoxManage.exe: error: Most likely, the VirtualBox COM server is not running or failed to start.

but it is still not working.

I've also installed the Oracle VM VirtualBox Extension Pack (can be downloaded here). But it simply doesn't want to work.

Would be great, if someone could help.

Thanks

System parameter:
Host: Winwows 7 64Bit
Guest: Debian 6.0.6 64Bit
VirtualBox: 4.2.6

EDIT:

Some additional information:

C:\Windows\system32>VBoxManage getextradata "Dev VM" enumerate
Key: GUI/LastCloseAction, Value: shutdown
Key: GUI/LastGuestSizeHint, Value: 720,400
Key: GUI/LastNormalWindowPosition, Value: 390,158,1424,819,max
Key: GUI/LastScaleWindowPosition, Value: 640,345,640,480,max
Key: GUI/MiniToolBarAlignment, Value: bottom
Key: GUI/SaveMountedAtRuntime, Value: yes
Key: GUI/ShowMiniToolBar, Value: yes
Key: VBoxInternal2/SharedFoldersEnableSymlinksCreate/M:\workspace, Value: 1
Key: VBoxInternal2/SharedFoldersEnableSymlinksCreate/M:\workspace\, Value: 1
Key: VBoxInternal2/SharedFoldersEnableSymlinksCreate/var/www, Value: 1
Key: VBoxInternal2/SharedFoldersEnableSymlinksCreate/var/www/, Value: 1
Key: VBoxInternal2/SharedFoldersEnableSymlinksCreate/workspace, Value: 1
Key: VBoxInternal2/SharedFoldersEnableSymlinksCreate/workspace/, Value: 1

So, the config changes have been saved. But they don't work.

It works!

On Windows by default only administrators can create symlinks. When I start VirtualBox as administrator, I can create symlinks without any problems.

In order to be able to create symlinks without starting the VB as admin, you need to set this permission for your user/usergroup. Here is a short how-to.

The only problem is -- I have not found a way to permit creating of symlinks to admin-users. I don't know, whether it's possible.