SHRegGetValueW could not be located in SHLWAPI.DLL

A problem I ran into last week with the accounting software upgrade was very strange. We have 3 Windows 2000 Professional workstations and 1 Windows XP Professional workstation in the Finance department. All 3 Windows 2000 Professionals systems exhibited the same problem. After I installed the Pervasive.SQL 8.1 client, then the Sage PFW client and then rebooted, the Windows logon prompt would come up. I would login as the user, or Administrator, and the blue desktop would load with no icons and the taskbar would flash for a moment, then disappear completely. I waited and waiting and nothing ever loaded. I could do CTRL + ALT + DEL to bring up the task manager, but trying to start Explorer.exe from the File --> New Task (RUN) wouldn't load the taskbar, again it would only flash and then disappear. I would also receive the following error message: "The procedure entry point SHRegGetValueW could not be located in the dynamic link library SHLWAPI.DLL" I also could not start Internet Explorer, but the system had Mozilla Firefox on it so I could run that. The only thing I could find on this problem was relating to Windows XP systems after applying Microsoft patch MS04-038. I re-installed the latest service pack 4 and rebooted, that didn't fix it. Next I ran the System File Checker utility and that detected some problems with the system DLL files. Use a slip-streamed CD of Windows 2000 Pro and Service Pack 4, then rebooting, I was able to get the system to come back up. Since then none of the three has exhibited any instabilities. It only took my 5 hours to figure this out and get them running.