The subject condition can exist of you have the following registry key, but without additional sub-keys:

HKEY_CURRENT_USER\Software\Clients\Mail.

This registry key may be created if you respond Yes the first time MSN Explorer prompts you with:

Would you like to get on the Internet and write e-mail through the Start Menu using MSN Explorer?

To resolve this issue, use the Registry Editor to delete the HKEY_CURRENT_USER\Software\Clients\Mail key.