Still no real clue what the import of this error is, but 169 is just the pid (process ID) of a /usr/libexec/UserEventAgent process, and so not significant in itself.
Such processes are kicked off by these:
/System/Library/LaunchAgents/com.apple.UserEventAgent-LoginWindow.plist
/System/Library/LaunchDaemons/com.apple.UserEventAgent-System.plist
/System/Library/LaunchAgents/com.apple.UserEventAgent-Aqua.plist
man UserEventAgent says, among other things
The UserEventAgent utility is a daemon that loads system-provided plugins to handle high-level system events which cannot be monitored directly by launchd(8). The UserEventAgent utility should not be invoked
directly
FILES
/System/Library/UserEventPlugins
/System/Library/UserEventPlugins contains ~40 plugins, none of which particularly attract my attention:
ACRRDaemon.plugin/
AirPortUserAgent.plugin/
AppleHIDMouseAgent.plugin/
AssistantUEA.plugin/
AutoTimeZone.plugin/
BTMMPortInUseAgent.plugin/
BluetoothUserAgent-Plugin.plugin/
BonjourEvents.plugin/
CalendarMonitor.plugin/
CaptiveSystemAgent.plugin/
CaptiveUserAgent.plugin/
DiskUnmountWatcher.plugin/
EAPOLMonitor.plugin/
GSSNotificationForwarder.plugin/
LocationMenu.plugin/
PrinterMonitor.plugin/
SCMonitor.plugin/
alfUIplugin.plugin/
com.apple.SoftwareUpdate.UserNotification.plugin/
com.apple.TimeMachine.System.plugin/
com.apple.TimeMachine.plugin/
com.apple.WorkstationService.plugin/
com.apple.bonjour.plugin/
com.apple.cfnotification.plugin/
com.apple.dispatch.vfs.plugin/
com.apple.fsevents.matching.plugin/
com.apple.iokit.matching.plugin/
com.apple.launchd.helper.plugin/
com.apple.locationd.events.plugin/
com.apple.notifyd.matching.plugin/
com.apple.opendirectory.matching.plugin/
com.apple.rcdevent.matching.plugin/
com.apple.smb.preferences.plugin/
com.apple.time.plugin/
com.apple.universalaccess.events.plugin/
com.apple.usernotificationcenter.matching.plugin/