Vista - WARNING: PopulateDataStore failed: 0xc8000402

I'm using the script provided in the MSDN to run an offline WUA scan on a
target machine (WIN 2003 SP 1).
After some run that go successful I get an error on the WUA and I can't
recover from that error.
The error in the Windwosupdate.log is:

DSParseUpdateSet, time, 12
2009-01-16 10:49:28:531 780 50c Perf, DSWSProcessSyncInfo, time, 930
2009-01-16 10:49:28:531 780 50c Perf, PopulateDataStore, time, 943
2009-01-16 10:49:28:531 780 50c PT WARNING: PopulateDataStore failed:
0xc8000402
2009-01-16 10:49:28:531 780 50c PT WARNING: Sync of Updates: 0xc8000402
2009-01-16 10:49:28:531 780 50c PT WARNING: SyncServerUpdatesInternal
failed: 0xc8000402
2009-01-16 10:49:28:531 780 50c Perf, SyncServerUpdates, time, 3222
2009-01-16 10:49:28:531 780 50c Agent * WARNING: Failed to synchronize,
error = 0xC8000402
2009-01-16 10:49:28:531 780 50c Perf, PrepareSearchCallbackInfo, time, 0
2009-01-16 10:49:28:937 780 50c Agent * WARNING: Exit code = 0xC8000402
2009-01-16 10:49:28:937 780 50c Agent *********
2009-01-16 10:49:28:937 780 50c Agent ** END ** Agent: Finding updates
[CallerId = DTMPatch]
2009-01-16 10:49:28:937 780 50c Agent *************
2009-01-16 10:49:28:937 780 50c Agent WARNING: WU client failed Searching
for update with error 0xc8000402
2009-01-16 10:49:28:937 780 50c Perf, CSearchCall::Execute, time, 22583

Why this error is occurring? What does it come up to produce it?
Thanks
Michele