Error: You receive a registry for extension error message when you start Outlook 2003
Cause: The following can be the possible cause:
This issue may occur because of a damaged Exchange Extensions string value in the registry.
This article describes about an error message in MS Outolook 2003.
Important: This section, method, or task contains steps that tell you how to modify the registry. However, serious problems might occur if you modify the registry incorrectly. Therefore, make sure that you follow these steps carefully. For added protection, back up the registry before you modify it. Then, you can restore the registry if a problem occurs. For more information about how to back up and restore the registry, click the following link in the iYogi Knowledge Base:
How to back up and restore the registry in Windows
Quit Outlook 2003.
Click Start and then click Run
Type regedit and then press Enter
Locate the following registry key:
Right click Exchange Extensions, and then click Modify.
Delete the value that is in the Value data box, and then type the following value in the Value data box:
Click OK to close the Edit String dialog box.
Close the Registry Editor
Restart the Computer
Try to access MS Outlook 2003