Comment 30 for bug 528094

I expected something like that to happen--it seems like with the .service file you listed, the destination object now calls 'xscreensaver -lock' as the executable, which does what is expected, but the "message name" = "org.gnome.ScreenSaver.Lock" is not recognized and no reply is made via DBUS. So that error is probably ignorable, at least as a work-around.

Maybe the .service file should have
   Exec=/usr/bin/xscreensaver-command
and the -lock option should be controlled by DBUS somehow via the "message name."

In fact, it seems that whenever I get a notification (new mail or network connect/disconnect, etc), the screen locks. That (the notifications program) must also be communicating with org.gnome.ScreenSaver, but sending a different message name. I am assuming that is because it wants to put the notification on top of the screen saver if it is active, so it has to get access. Now, it just locks the screen, since that is what is done whenever DBUS calls the service.

Again, it would be great for someone with more knowledge of DBUS to look into this.

So, this is not a complete work-around or patch, since it results in undesired behavior. :( In fact, I may remove the .service file.