WMI Error 0x80070005

Hi,

On a lot of Windows XP SP2 machines in our domain, I am gettting WMI Errors.
I am not able to run any WMI scripts.

When I run wbemtest and click connect and connect using the default settings
(
to root\default,
Using : IWbemLocator (Namespaces)
and no credentials (ie. with logged on user)
)

I get the an error as following
Number: 0x80070005
Facility: Win32
Description: Access is denied.


Then I check using wmimgmt.msc and when I right click WMI Control and
connect to the local computer it gives the following message in General tab.
Failed to connect to <local computer> because "Win32: Access is denied."

Also I tried recompiling the mof files and again I get the errors as
****
Parsing MOF file: c:\windows\system32\wbem\cimwin32.mfl
MOF file has been successfully parsed
Storing data in the repository...
An error occurred while opening the namespace for object 1 defined on lines
6 - 6:
Error Number: 0x80070005, Facility: Win32
Description: Access is denied.
Compiler returned error 0x80070005
****

I notice by openeing the source files that the error is always around the
lines as following:
Instance of __Namespace
{
Name = "CIMV2";
};

Name = "xxxx" for different mof/mfl files

So I guess there's some problem in namespace, or soe permissions somewhere.
I ran dcomcnfg and checked settings for WMI object and all the settings were
default , ie same as the one on another comp, where WMI is working properly.

I have tried searching the internet but have not been able to comeup with a
solution, not even able to diagnose what is the problem.

Could some one please point out what all I can try to rectify this problem.
This is really becoming a major problem as I am not able to run a lot of WMI
scripts on the machines.

tia
Hursh