Failed to add a plugin to the panel

Hi before logging a bug I would consult the community on following. In the console I type: kfmclient exec settings:/ or kfmclient openURL settings:/ which opens the settings in konqueror, but then I open "Peripherals" or whatever is called in English and press Mouse. I get Failed to add a plugin to the panel No running instance of xfce4-panel was found WTH? Any idea? Anyone else can reproduce this? I've never used xfce thanks regards