Exchange Setup does not work because of a COM+ issue and error code 0xc103798a (318731)

RESOLUTION

Warning If you use Registry Editor incorrectly, you may cause serious problems that may require you to reinstall your operating system. Microsoft cannot guarantee that you can solve problems that result from using Registry Editor incorrectly. Use Registry Editor at your own risk.
To resolve this issue:

1. Make sure that the Microsoft Distributed Transaction Coordinator service (MS DTC) is started. By default, this service is installed with Microsoft Windows 2000. If this service is stopped, the error messages that are mentioned in the "Symptoms" section of this article may occur. The MS DTC service is required by Microsoft Exchange setup. The MSDTC service is also required during the installation of an Exchange hotfix or service pack.
   
   If the MS DTC service does not start, you may have to reinstall the service.
   
   For additional information about how to reinstall the service, click the following article number to view the article in the Microsoft Knowledge Base:

   279786 How to reinstall MS DTC for a nonclustered Windows 2000 Server

   COM+ is required to register Cdowfevt.dll, and COM+ requires that the MS DTC service be running on the server. The MS DTC service must be running for either Exchange Setup or an Exchange 2000 service pack installation to complete properly. This applies to both clustered and non-clustered Exchange servers.
   
   On a cluster, the MS DTC service must be running on both nodes. For additional information about this issue on a clustered Exchange 2000 server, and about how to install the MS DTC service on a cluster, click the following article number to view the article in the Microsoft Knowledge Base:

   312316 Setup does not install Exchange 2000 on a cluster if the MSDTC resource is not running

2. If the MS DTC service is running, the error messages that are mentioned in the "Symptoms" section of this article may be caused by a damaged COM+ catalog. This may be the cause even if you can use the Component Services management console (COM+ Explorer) without experiencing any issues. You can usually repair a damaged COM+ catalog by reinstalling COM+. To reinstall COM+:
   1. In the %SystemRoot%\System32 folder, rename the Clbcatq.dll file to ~clbcatq.dll. Make sure that you include the tilde (~) at the beginning of the file name. If there is already a ~clbcatq.dll file in the %SystemRoot%\System32 folder, move the ~clbcatq.dll file out of the folder or rename the ~clbcatq.dll file first. If the file is in use, you may have to use the rename command from an MS-DOS prompt to rename the file.
   2. Save and delete the HKEY_LOCAL_MACHINE\Software\Microsoft\COM3 key. To do so:
      1. Start Registry Editor (Regedt32.exe).
      2. Locate and click the following key in the registry:

         HKEY_LOCAL_MACHINE\Software\Microsoft\COM3

      3. On the Registry menu, click Save Key, and then save the key to a file.
      4. Make sure that the HKEY_LOCAL_MACHINE\Software\Microsoft\COM3 key is still selected. Either press the DELETE key or right-click the key, and then click Delete.
      5. Quit Registry Editor.
   3. In Control Panel, open the Add or Remove Programs tool, and then open the Add/Remove Windows Components tool. Do not make any changes, just click Next. This reinstalls COM+.
3. If reinstalling COM+ does not work, you may have to rebuild the COM+ catalog entirely. Typically, you have to start in Safe mode to keep Windows File Protection from reversing the changes. To rebuild the COM+ catalog:
   1. Start in Safe mode.
   2. In the %SystemRoot%\System32 folder, rename the Clbcatq.dll file to ~clbcatq.dll. Even in Safe mode, this file will be in use. However, you can use the rename command from a command prompt to rename the file.
   3. In the %SystemRoot% folder, make a backup copy of the Registration folder, and then try to delete the contents of the folder. Typically, there is one file in the Registration folder that is in use and cannot be deleted. However, after you restart the server in Normal mode, you can remove the file.
   4. Save and delete the HKEY_LOCAL_MACHINE\Software\Microsoft\COM3 key:
      1. Start Registry Editor.
      2. Locate and click the following key in the registry:

         HKEY_LOCAL_MACHINE\Software\Microsoft\COM3

      3. On the Registry menu, click Save Key, and then save the key to a file.
      4. Make sure that the HKEY_LOCAL_MACHINE\Software\Microsoft\COM3 key is still selected. Either press the DELETE key or right-click the key, and then click Delete.
      5. Quit Registry Editor.
   5. Start in Normal mode.
   6. In the %SystemRoot% folder, remove the Registration folder. At this point any remaining files in the folder should no longer be in use.
   7. In Control Panel, open the Add or Remove Programs tool, and then open the Add/Remove Windows Components tool. Do not make any changes, just click Next. This reinstalls COM+, which builds a new registration catalog.
4. After you complete the preceding steps, you must reinstall any programs that have to register with COM+. On an Exchange server, you must at minimum:
   1. Remove Internet Information Services (IIS), and then install it again.
   2. In the Exchange Setup program, reinstall Exchange.
   3. Apply any Exchange 2000 necessary service packs.

After you create the clean COM+ catalog, you should be able to successfully reinstall Exchange 2000 and the service pack update.

Note This article applies to both:

• Exchange on a computer that is running Microsoft Windows 2000 Server. -and-
  
  
• Exchange on a computer that is running Microsoft Small Business Server 2000.