"Volume Shadow copy operation failed for backup volumes..."

Hi
I working on WinSrv2008 Core (with SP2) and from a few days I have a little problem with wbadmin and vss. When I try make backup I get couple times:

EventID 12292
"Volume Shadow Copy Service error: Error creating the Shadow Copy Provider COM class with CLSID {65ee1dba-8ff4-4a58-ac1c-3470ee2f376a}  [0x80080005]
Operation:
   Obtain a callable interface for this provider
   Query volumes supported by this provider
Context:
   Provider ID: {b5946137-7b9f-4925-af80-51abd60b20d5}
   Class ID: {00000000-0000-0000-0000-000000000000}
   Snapshot Context: 29
   Provider ID: {b5946137-7b9f-4925-af80-51abd60b20d5}
   Snapshot Context: 29"

and

EventID 11
"Volume Shadow Copy Service information: The COM Server with CLSID {65ee1dba-8ff4-4a58-ac1c-3470ee2f376a} and name SW_PROV cannot be started. Most likely the CPU is under heavy load. [0x80080005]
Operation:
   Obtain a callable interface for this provider
   Query volumes supported by this provider
Context:
   Provider ID: {b5946137-7b9f-4925-af80-51abd60b20d5}
   Class ID: {00000000-0000-0000-0000-000000000000}
   Snapshot Context: 29
   Provider ID: {b5946137-7b9f-4925-af80-51abd60b20d5}
   Snapshot Context: 29"

and for end I always get this:

EventID 521
"Backup started at '2009-07-20T23:33:46.578000000Z' failed as Volume Shadow copy operation failed for backup volumes with following error code '2155348075'. Please rerun backup once issue is resolved."

I search on TechNet and other forums and I found some similar problems but any proposed solutions are not effective.
Any idea to resolve this problem ??


--
OK, I found source of problem
Service "MS Software Shadow Copy Provider" can't start.
Error 2: The system cannot find the file specified

When I try:
regsvr32 /i swprv.dll
I got message that dll was loaded but I got error 0x8000ffff

I found a manual solution to fix this. I checked in regedit this key:
[HKLM\SYSTEM\CurrentControlSet\Services\swprv]
and compare it with another WS08 instance.

I found then missing that key:
[HKLM\SYSTEM\CurrentControlSet\Services\swprv\Parameters]
I create "Expandable String Value":
Name: ServiceDll
Value: %Systemroot%\System32\swprv.dll

And service swprv works :)
Backup start normally.
Problem solved!