UPDATE... I think maybe I misunderstood how KACE reported registry keys.
"did not succeed: (0)" must mean that it could not find the key, not that an error occurred.

Anyways, this appears to be working with mramsdell's HKLM64 recommendation.

Verify
Verify that “HKLM64\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon!Userinit” is equal to “C:\Windows\system32\userinit.exe,C:\Windows\System32\KUsrInit.exe,”.

On Success
Set “HKLM64\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon!Userinit” to “C:\Windows\System32\KUsrInit.exe,”.

Ok- what I'm really trying to do is fix that Userinit issue that the KACE agent causes - where the My Documents opens on log in. I was just using the "HKLM\SOFTWARE\CRW!RUNTIME_VERSION" key as a test because I know it exists on our different environments.

I don't just want to blindly go about updating the registry on computers for the off chance that the computer already has a modified Userinit key.

It just seems like the registry features of scripting do not work properly on Windows 7 x64 SP1 machines (and possible other x64 machines).

Does anyone have this (or any registry items) actually working on x64 machines?

I had this same issue. the issues is that you are querying a 64 bit registry from a 32 bit system(kbox). try HKLM64\SOFTWARE\ instead of HKLM\SOFTWARE\

I'm running into a similar issue and it's due to the way that Microsoft handles (protects?) access/display of the registry under x64 Windows (see http://support.microsoft.com/kb/896459 ). See if the keys you are looking for are available under HKLM\Software\Wow6432Node\...  I am trying to work through an issue with CustomInventory rules (see http://www.appdeploy.com/messageboards/fb.asp?m=89448 ) and it sounds like you may be running into a similar challenge.

On the x64 PC, is the entry under HKLM\Software\CRW or HKLM\Software\Wow6432Node?

Casey