Event log errors

I am getting the following error in the event log of my Win2K Pro machine, sample below -

Event Type: Error
Event Source: Userenv
Event Category: None
Event ID: 1000
Date: 20/10/2003
Time: 02:48:00
User: NT AUTHORITY\SYSTEM
Computer: P1000
Description:
Windows cannot unload your registry class file. If you have a roaming profile, your settings are not replicated. Contact your administrator.

DETAIL Access is denied. , Build number ((2195)).



I have found the following MS Q319909 that references it http://support.microsoft.com/default.aspx?scid=kb;en-us;319909&Product=win2000. However, this says it was fixed in SP3 or at least post-SP3. I'm on SP4.

Going by the timing of the events, I think the error is being generated by an scheduled hourly task that runs under an Admin a/c. A 2nd reason for the association is that the hourly task [that runs a BATch file] suddenly stops working by deciding to never finish properly even though the last line being "echo finished >> logfile.txt" is actioned. I know that Win2000 thinks it is still running, & hence won't run it in the future, because Sched Tasks shows "running" when I log on to the Admin a/c & check. Only a reboot frees it up to allow the task to run as per the schedule.

I suspect that a trigger for the problem could be when an ordinary user has being logged on the machine (@ event time?), but can't be absolutely sure of that - never been able to reproduce it despite trying.

Anyone any ideas on this problem?