Windows 2000 upgrade

After upgrading my windows 98 operating system to windows 2000 I?m having a problem. When I right click on my computer, network neighborhood, and other icons on the desktop. I?m getting this error message. ?CWBNACFS.DLL cannot run. Unable to get a handle CwbRdr.? Then when I hit ok the message will go away and show the properties. I have no clue why this is happening. Any help is greatly appreciated. Thanks a lot.