Agent installation / Upgrade fails

Installing the SCOM 2007 /SCE agent to the Windows Server 2003 I have the following problem with one of them:

the installation fails everytime with error "The MOM Server could not execute WMI query "Select * from Win32_Environment where NAME='PROCESSOR_ARCHITECTURE'" on computer fqdncomputername.

Operation: Agent install

Error Code: 80004005

Error Description: unknown error."

resolution:

Logon with administrative privileges to the affected machine, start REGEDIT, create a new REG_SZ value PROCESSOR_ARCHITECTURE at HKEY_Current_User\Environment identically the existing one at HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Session Manager\Environment.