Just noticed something weird:

I think the links the installer creates are wrong for the might and magic 4-5 pack....

Linkname Game
Might and Magic 4-5 World of Xeen is Might and Magic 4-5: World of Xeen
Might and Magic 4-5 World of Xeen (Full Speech) is Might and Magic 5: Darkside of Xeen
Might and Magic Swords of Xeen is Might and Magic: Sword of Xeen (FANMADE EPISODE, not really a part of Might and Magic at all!)

But the real Might and Magic 4: Clouds of Xeen is missing...

i am a bit confused ..

What do you mean? Do you want to play the standalone Clouds of Xeen?
World of Xeen is Clouds and Darkside combined, and you start on Clouds. So you won't miss anything.

Actually World of Xeen (Full Speech) is World of Xeen too, not just Darkside. The only difference is you get full digitized speech for all encounters.

Like Petrus wrote, World of Xeen is combination of Clouds and Darkside. It also adds some new areas after both are completed.

Unfortunately you can't get the standalone Clouds of Xeen and Darkside of Xeen. But the only thing you'll miss are the (very nice) main menus.

You can play Darkside standalone game (if only to see the menu) if you follow my instructions in third post here:
http://www.gog.com/forum/might_and_magic_series/is_there_any_way_to_get_the_original_4_and_5_manuals