Xgrid: agentcontrollerpassword called without being authenticated

I'm setting up Xgrid as a client on OSX Intel 10.5.5, precisely according to http://www.macresearch.org/contribute_to_openmacgrid

After that though, it doesn't do anything. The CPU load stays low, even though Xgridagentd and Xgridagenthelper are both running in Activity Monitor - at 0% CPU and 5MB of real RAM. Curiously, the log reads:

...System Preferences[551]: Admin.xgridAgentControllerPassword: called without first being authenticated

I'm new to Xgrid, Googling has not helped. Thanks, any help appreciated.