http://support.microsoft.com/kb/932520
On a Windows Vista-based computer or on a Windows Server 2008-based computer, the Microsoft ISATAP adapter appears with a yellow exclamation mark next to it in Device Manager, and you also receive an error message
Symptoms:
On a Windows Vista-based computer or on a Windows Server 2008-based computer, the Microsoft ISATAP adapter appears with a yellow exclamation mark (!) next to it in Device Manager. Additionally, when you open the properties dialog box for the device, you receive an error message that resembles the following:
Windows cannot load driver (Code 31)
(...)
Resolution:"You can safely ignore this error message. This error message does not indicate a problem with the adapter. The adapter will continue to work correctly. "
