Driver Signing Preventing Exchange 2003 from Installing

I was installing exchange 2003 on windows server 2003 SP2, and every dll file it tried to copy it would pop up with:

The driver software you are installing has not been properly signed with Authenticode(TM) technology. Therefore, Windows cannot tell if the software has been modified since it was published. The publisher's identity cannot be verified because of a problem:
The parameter is incorrect.



Whenever I clicked Yes, it would pop up again for the next file resulting in a very slow exchange 2003 installation. With a bit of hunting around I found out the registry key to stop Authenticode from warning every file located under:

HKLM\Software\Microsoft\Non-Driver Signing

Set Policy to 00

Before:


After:


After making this change the setup completed successfully and the Security Alert - Driver Signing message stopped popping up and the installation completed successfully.