If this is 64-bit the DLLS, etc., need to be copied into the WINDOWS\sysWOW64 folder, not WINDOWS\System32 and registry entries need to go in the HKLM\Wow6432Node key. The GOG version of MoE bypasses the Indeo codec problem by setting the game's compatibility mode to run at 640x480 resolution. Here is an Indeo installer you can try that worked on my Win7 x64. With it, I am able to see the AVIs.
Edit: I just installed the game on my Win7 x64. I already had the Indeo installed on my system from working on the MoE installer. I believe that the Indeo is the culprit. Like many of the Sierra games of this era, the very first thing that happens as the game starts is that it tries to play the sierra.avi. This has caused problems with other games on modern PCs. GK3 is a perfect example. The game starts on my system without setting compatibility mode or anything else. As I said, GOG got around this by forcing MoE to run at 640x480.
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