posted 07-04-10 02:45 AM EDT (US)   
This error has happened to me, I didn't know how to solve it, until I remembered I screwed with the Registry of Windows. I have heard of this problem from other people.

Click for picture

This problem rises because of changes in Registry doing with the EE:AOC Keys, I have found all of these keys and they are as follows (This is how it should be for what I know):

My PC
HKEY_LOCAL_MACHINE
Software
Mad Doc Software
Empire Earth - The Art of Conquest
1.0.0.0 <---This will be always like this, unless they make an official patch and you install it.
Empire Earth Difficulty Setting and Multiplayer Lobby Add-on
2.0.0.0 <---Must be this, this addon comes with the version 2 so it must be that if you have it, other than that, if you don't, it must not exist.
Sierra
CDKeys <---Don't ever edit these entries, only way to fix them is reinstalling game and entering CD key again.
EEAOC [Your CDKEY Encoded]
Empire Earth [Your CDKEY Encoded]
Sierra OnLine
Setup
EEAOC <---If you installed EE AOC, you must have this
Directory [Installation path of game] <---Will vary
Full Name [Empire Earth - The Art of Conquest]
EEARTH
Directory [Installation path of game]
Full Name [Empire Earth]
Sierra On-Line
Empire Earth
1.0.0.0 or 1.0.4.0 or 2.0.0.0 <---Depending on the version you have
Empire Earth - The Art of Conquest
1.0.0.0 <---Again, unless they make official patch, this must be.
Stainless Steel Studios
Empire Earth
1.00.000 <---For all I know, this is how it must be, I find some people not to have this, so maybe this is not needed.

And that's it, you can find the program on the WINDOWS path, it's named "regedit.exe". If you have any questions or suggestions to add on the post, contact me at dietrevers@gmail.com.

[This message has been edited by Dietrevers (edited 07-04-2010 @ 02:11 PM).]