Perflib Errors

If you see a whole stack - every 5 minutes - of Perflib errors (ID:
1023) in the Application Event Log.
This is basically telling you that the Performance Counters for some
services have been corrupted.

The solution may be to re-install the applications (or replace the
related DLL) or to remove the Performance Counters for those services
entirely:

http://support.microsoft.com/kb/247226

here is another couple of references:

http://ferventcoder.com/archive/2008/08/10/possible-performance-counter-corruption-or-performance-counters-are-just-disabled.aspx

http://blogs.microsoft.nl/blogs/tonykrijnen/archive/2007/01/26/9958.aspx