Remotely reading HKLM registry key

I have been successful in reading the registry on remote Vista systems --for
the most part. I have no trouble reading the HKCU keys. I can read most of
the HKLM keys. However, I have found that some of the HKLM keys are not
accessible for reading. For example, I can read any value within the
following remote registry key:

HKLM\SOFTWARE\Microsoft\Windows NT\CurrentVersion

But if I try to read any value within this remote registry key it fails with
a permission error (5):

HKLM\SOFTWARE\Microsoft\Windows NT\CurrentVersion\ProfileList

Another example...

I can enumerate all of the remote registry keys below the following key:

HKLM\SOFTWARE\Microsoft\Windows NT\CurrentVersion

But I cannot enumerate all of the remote registry keys below this key:

HKLM\SOFTWARE\Microsoft\Windows NT\CurrentVersion\ProfileList

I have checked the permissions of the keys in question and I see no
difference between the keys I can read and the keys I cannot read.
Obviously, I am admin on both machines or I wouldn't even have been able to
read the remote keys that I am able to read. I have insured that when I
access the keys that I pass only KEY_READ as the access parameter. This
issue only occurs when reading the keys remotely. If I run my program on the
local Vista system in question I have no issue reading ANY key within HKLM.

Does anyone have a clue as to why only specific HKLM keys are being blocked
and how to overcome that?

Any input would be helpful.

JW