A recent Microsoft XP update has introduced problems with User32.dll and HHCTRL.OCX Windows system files, affecting quite a few programs including ECOTECT. However, this is quite easily fixed.

Since April 2007 we have been receiving reports of an error when running our software after users have installed a Windows XP Update (KB925902). Many other applications from other software vendors have also been affected by this, so Microsoft have releases a HotFix to sort the problem out.

User32.dll & HHCTRL.OCX Clash

The error message displayed is something like:

The system DLL user32.dll was relocated in memory. The application will not run properly. The relocation occurred because the DLL C:\Windows\System32\Hhctrl.ocx occupied an address range reserved for Windows system DLLs. The vendor supplying the DLL should be contacted for a new DLL.

Solution

The solution is to install a Microsoft hotfix that you can download directly from:

      Windows 935448 Package (microsoft.com)
      or
      WindowsXP-KB935448-x86-ENU.exe (squ1.com)

For more details and discussion on this topic, see the original ECOTECT bug report "Missing DLL" or read the Microsoft Knowledge Base article no. 935448 on this issue.

ECOTECT isn't the only program to be hit with this issue. It is essentially a conflict between two different Windows updates. It occurs after you install security update 925902 (MS07-017) and security update 928843 (MS07-008). The HHCTRL.OCX file that is included in security update 928843 and the User32.dll file that is included in security update 925902 have conflicting base addresses. ECOTECT uses both the HHCTRL.OCX for interacting with the HTML Help ActiveX system and the User32.dll for standard windows controls and dialog boxes, hence the conflicting base addresses result in an error message.

Simply download and run the hotfix provided above to install a new HHCTRL.OCX with the base address sorted out.