Last time I run on Windows7 and can't access the "HKEY_LOCAL_MACHINE/SOFTWARE/Microsoft", I forget to mention in that post I had resolved after running the cmd.exe as administrator. That does have difference on Windows7 system. For Win7 I have to run something as administrator, otherwise reading some part in reg may be denied though I do login as administrator.
This time I'm running on windows 2003 server. I just tried it on Win7 with administrator, but I'm still refused to access the keys under the "Updates", just the same as on win2003.