Remote registry request access denied

I have a program that requests performance counter information from
remote Vista machine. In its simplest form it is just a single line o
Visual Basic code:

PerformanceCounterCategory.Exists("Memory", remotemachinename

If I run as an admin (admin accounts on both machines) everything i
fine. But if i run as a standard account (non-Admin on both machines)
get an access denied error on "openHKPD". That is the hidden registr
hive HKEY_PERFORMANCE_DATA. Anyone have ideas about why a standar
account would fail? It does not fail if I run the request locally on th
machine so the standard account has sufficient permission

If I run from Vista to a remote XP machine I do not get this error so
am thinking it may have something to do with registry virtualization o
Vista. Or it may have something to do with UAC except these ar
non-Admin accounts so UAC should not matter.

FYI Remote registry service is running and the registry ke
....\securepipeservers\winreg has granted permission to the non-Admi
account

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DreamU