Constant WSUS client error: 0xc8000408

Client server unable to load updates due to following output from windowsupdate.log:

2010-04-08 13:23:45:730 4952 1170 AU #############
2010-04-08 13:23:45:730 4952 1170 AU ## START ## AU: Search for updates
2010-04-08 13:23:45:730 4952 1170 AU #########
2010-04-08 13:23:45:730 4952 1170 AU <<## SUBMITTED ## AU: Search for updates [CallId = {B11FAE35-7860-4294-9D88-A41C20EC93E4}]
2010-04-08 13:23:45:745 4952 11c4 Agent *************
2010-04-08 13:23:45:745 4952 11c4 Agent ** START ** Agent: Finding updates [CallerId = AutomaticUpdates]
2010-04-08 13:23:45:745 4952 11c4 Agent *********
2010-04-08 13:23:45:745 4952 11c4 Agent * Online = Yes; Ignore download priority = No
2010-04-08 13:23:45:745 4952 11c4 Agent * Criteria = "IsHidden=0 and IsInstalled=0 and DeploymentAction='Installation' and IsAssigned=1 or IsHidden=0 and IsPresent=1 and DeploymentAction='Uninstallation' and IsAssigned=1 or IsHidden=0 and IsInstalled=1 and DeploymentAction='Installation' and IsAssigned=1 and RebootRequired=1 or IsHidden=0 and IsInstalled=0 and DeploymentAction='Uninstallation' and IsAssigned=1 and RebootRequired=1"
2010-04-08 13:23:45:745 4952 11c4 Agent * ServiceID = {3DA21691-E39D-4DA6-8A4B-B43877BCB1B7} Managed
2010-04-08 13:23:45:745 4952 11c4 Agent * Search Scope = {Machine}
2010-04-08 13:23:45:745 4952 11c4 Misc FATAL: Failed to delete file C:\WINNT\SoftwareDistribution\DataStore\Logs\edb.log (hr = 80070020) after 0 retries
2010-04-08 13:23:45:761 4952 11c4 DtaStor WARNING: Forcing re-creation of data store
2010-04-08 13:23:45:792 4952 11c4 DtaStor FATAL: Failed to initialize datastore, error = 0xC8000408
2010-04-08 13:23:45:792 4952 11c4 PT WARNING: PTError: 0xc8000408
2010-04-08 13:23:45:823 4952 11c4 DtaStor FATAL: Failed to initialize datastore, error = 0xC8000408
2010-04-08 13:23:45:823 4952 11c4 Agent * WARNING: Exit code = 0xC8000408
2010-04-08 13:23:45:823 4952 11c4 Agent *********
2010-04-08 13:23:45:823 4952 11c4 Agent ** END ** Agent: Finding updates [CallerId = AutomaticUpdates]
2010-04-08 13:23:45:823 4952 11c4 Agent *************
2010-04-08 13:23:45:823 4952 11c4 Agent WARNING: WU client failed Searching for update with error 0xc8000408
2010-04-08 13:23:45:823 4952 11dc AU >>## RESUMED ## AU: Search for updates [CallId = {B11FAE35-7860-4294-9D88-A41C20EC93E4}]
2010-04-08 13:23:45:823 4952 11dc AU # WARNING: Search callback failed, result = 0xC8000408
2010-04-08 13:23:45:823 4952 11dc AU # WARNING: Failed to find updates with error code C8000408
2010-04-08 13:23:45:823 4952 11dc AU #########
2010-04-08 13:23:45:823 4952 11dc AU ## END ## AU: Search for updates [CallId = {B11FAE35-7860-4294-9D88-A41C20EC93E4}]
2010-04-08 13:23:45:823 4952 11dc AU #############
2010-04-08 13:23:45:823 4952 11dc AU AU setting next detection timeout to 2010-04-08 13:23:20
2010-04-08 13:23:45:823 4952 11dc AU Setting AU scheduled install time to 2010-04-11 03:00:00
2010-04-08 13:23:45:855 4952 11dc DtaStor FATAL: Failed to initialize datastore, error = 0xC8000408
2010-04-08 13:23:45:855 4952 11dc AU FATAL: Failed to get session from datastore, error = 0xC8000408
2010-04-08 13:23:50:823 4952 11c4 Report REPORT EVENT: {4811264D-6CA1-4205-B0E9-1E3D41B1BBD2} 2010-04-08 13:23:45:823+0100 1 148 101 {00000000-0000-0000-0000-000000000000} 0 c8000408 AutomaticUpdates Failure Software Synchronization Windows Update Client failed to detect with error 0xc8000408.
2010-04-08 13:25:29:870 4952 11c4 DtaStor FATAL: Failed to initialize datastore, error = 0xC8000408
2010-04-08 13:25:29:870 4952 11c4 PT WARNING: PTError: 0xc8000408
2010-04-08 13:25:29:870 4952 11c4 PT WARNING: Initialization failed for Protocol Talker Context: 0xc8000408
2010-04-08 13:25:29:870 4952 11c4 Report WARNING: Reporter failed to upload events with hr = c8000408.
2010-04-08 13:47:02:877 4952 11c4 DtaStor FATAL: Failed to initialize datastore, error = 0xC8000408
2010-04-08 13:47:02:877 4952 11c4 PT WARNING: PTError: 0xc8000408
2010-04-08 13:47:02:877 4952 11c4 PT WARNING: Initialization failed for Protocol Talker Context: 0xc8000408
2010-04-08 13:47:02:877 4952 11c4 Report WARNING: Reporter failed to upload events with hr = c8000408.
2010-04-08 14:00:47:887 4952 11c4 DtaStor FATAL: Failed to initialize datastore, error = 0xC8000408
2010-04-08 14:00:47:887 4952 11c4 PT WARNING: PTError: 0xc8000408
2010-04-08 14:00:47:887 4952 11c4 PT WARNING: Initialization failed for Protocol Talker Context: 0xc8000408
2010-04-08 14:00:47:887 4952 11c4 Report WARNING: Reporter failed to upload events with hr = c8000408.

This log script occurs AFTER I have:
1 - Stopped AU service
2 - renamed/deleted the contents of the DataStore folder and/or renamed the SoftwareDistribution folder
3 - Restarted AU service

I've noticed than on all my Google searches for error 0xc8000408, that the above 3 steps pretty much remedy this situation, but no luck here.

Also, I've noticed that when the AU service ie restarted and the DataStore folder is re-created, it contains these log files: edb; edb, edb0000D, edb0000E, edb0000F, edbtmp, res1, res2, tmp.edb..
However, 45 minutes later, these files are no longer present (except one single text file named 'edb')

Any ideas??

many thanks,

Fla