"No Instances" seen for Instrumentation with EntLib2 in Perfmon

[Codex Twin]

After installing Instrumentation in EL2, I switched on instrumentation by
setting PerformanceCountersEnabled to true via the Exterprise Library
Configuration Console tool.

In perfmon it installed Performance objects for:
Caching
Cryptography
Data
Exception
Logging
Security

I saw the counters and instances for all these objects.
However, after a reboot, I noticed that the instances for the counters have
disappeared and have been replaced with "<No Instances>"

Any idea why this has occurred and how the problem can be fixed to do
Instrumenation with performance monitors.

Thanks