You may receive the subject error, if Windows 2000 incorrectly reads the digital signature and the local policies for Unsigned driver installation behavior and Unsigned non-driver installation behavior are set to Do not allow installation.
To work-around this issue, temporarily set the polices to Silently succeed, when updating a driver or installing a service pack or hotfix:
1. Start / Run / MMC / OK.
2. Press Add/Remove Snap-in, on the Console menu.
3. Press Add and select Group Policy and press Add.
4. Press Finish / Close / OK.
5. Navigate through:
Local Computer Policy
6. Right-click Unsigned driver installation behavior and press Security. Toggle the Local policy setting to Silently succeed and press OK.
7. Right-click Unsigned non-driver installation behavior and press Security. Toggle the Local policy setting to Silently succeed and press OK.