ARDAgent errors

I'm getting the following error repeated every few seconds in my system log on a 10.4.11 file server: [color=Blue]ARDAgent [10663]: DT_ConnectToTaskServer_Thread: Failed to find key for task server.[/color] ARD Admin is not installed or running on this machine. If I turn off Remote Management in the System Preferences, the error goes away (and so does my ability to ARD in).