GPMC Group Policy Results viewer error

I am running Vista XP2, connecting to a Server 2003 domain. I have installed
the updated RSAT on my system, but when I try to access the Group Policy
Results Wizard portion of GPMC, I get the following error:

An error occurred while generating report:
Item has already been added: Key in dictionary: 'MSS: (AutoAdminLogon)
Enable Automatic Logon (not recommended)'
Key being added: 'MSS (AutoAdminLogon) Enable Automatic Logon (not
recommended)'

I have tried running the GPRW against several computers with the same
message. I have tried agains both XP and Vista computers.

The computer is domain member? What do you mean with the updated RSAT tools?
Which account are you using om the Vista machine and is specified in GPRW?
Does the account have a password configured?

[bo.cato]

I ran into this too and saw that no one has bothered to put an answer in a year so here ya go.

Quick fix:

You can still edit the policy even if the html view doesn't show. Edit the policy that is blowing up. Find the key that is being bad, in this example it's the MSS (AutoAdminLogon) Enable Automatic Logon setting. This is found under local security, security options in gpmc. You will see 2 MMS (AutoAdminLogon) entries. The issue is both are defined. The parser doesn't like that. Quick fix is change the first one to undefined. Leave the second one defined (so it will take effect if that's what you want). The key is both can't be defined. Ta da it's fixed but this is ugly.

Better fix:

Find the adm (or admx / adml if 2008) template that has the entry twice. Either remove the template or edit it out with notepad.