Last week I loaded the April 3 Security Update from Microsoft onto my work computer.
http://www.microsoft.com/athome/security/update/bulletins/200704OOB.mspx
This update was marked as Critical and was released early just to get it in circulation. Unfortunately it created a .dll conflict error.
RTHDCPL.EXE – Illegal System DLL Relocation
The system DLL user32.dll was relocated in memory. The application will not run properly. The relocation occurred because the DLL C:\system32\HHCTRL.OXC occupied an address range reserved for Windows system DLLs. The vendor supplying the DLL should be contacted for a new DLL.
In all my years of computing I have never before seen that error. I restored my system to an earlier date and again loaded the update with the same results. I searched in vain on the Microsoft website to find an explanation for this error. While the computer seemed to perform correctly, I wanted to be sure my system was ok.
I looked up all the .dll files mentioned in the error message and found that the one triggering the error was a RealTek audio driver. I went to the RealTek site and downloaded their HD audio update and I no longer get the error message.
Why there was conflict between Microsoft and RealTek I don’t know but I hope the security update was really that important.
UPDATE
After this blog was posted, Microsoft released a patch.
Update for Windows XP (KB935448)
Date last published: 4/10/2007
Download size: 702 KB
Install this update to resolve an issue where certain third-party applications may not start, and you receive an error message: “Illegal System DLL Relocation” after you install security update KB925902 (MS07-017). After you install this item, you may have to restart your computer.