Windows 2003 (SP2/R2/Whatever) gives you the following errors:

Event ID 35
Source : WinMgmt
Category : None
Type : Warning
WMI ADAP was unable to load the ASP.NET_2.0.50727 performance library
because it returned invalid data: 0x0

and

Event ID 40
Source : WinMgmt
Category : None
Type : Warning
WMI ADAP was unable to create the object
Win32_PerfRawData_ASPNET_2050727_ASPNETAppsv2050727 for Performance Library
ASP.NET_2.0.50727 because error 0x80041001 was returned

Some internet forum posts tell you that there is a hotfix @ Microsoft CSS. This is not true.
This problem has been fixed in Microsoft .net Framework 3.5 SP1 which will be released somewhere summer 2008 (currently there this product is in beta).

If anyone has information on how to filter these events from the eventlog (which is a solution to some people), please let me know.

Edit – 4 June 2008
As mentioned in the comments below by Carloc, there is a hotfix available on request (no KB article yet, you have to mention the number 951683. See Carloc’s page for the full story.