Ok first of all nice way to describe your problem, 2nd of all don't quatro post (if that's even a word) instead use the Edit button. 3rdly why are you importing models with the Campaign Editor and not the Import Manager? Also if a model has a skin, texture (.BLP file) make sure you remove the war3mapimported/ from the path.
I'm using the Campaign Editor because I'm making a campaign with the units in almost every level. And I did change the paths. Here is what happened in order.
1. I imported all models via Campaign Editor's Import Manager
2. I made custom units
3. I scaled them to size which is when the first black boxes occured + the yellow text at the bottom left saying Invalid ID, though I didn't make much of it because it was working fine.
4. I placed units randomly
5. I created an avatar of vengeance hero giving it both ranged and melee attack.
6. I wanted to test if the attack worked so I placed him.
7. I tested the map
8. He didn't appear
9. I used iseedeadpeople to check if anything appeared, and nothing did.
10. I posted this with the orginal problem
11. I played some WCIII games waiting for replies
12. I went to check on this and the map, which no longer had any units on it.
13. I pressed the undo then redo button both once, and black boxes appeared where I placed the units and spam at the bottom left of screen said Invalid ID about 3 times even though I placed about 20 units (though 3 models)
14. I tried to replace the units but when I opened the Unit Palette, nothing appeared at custom.
15. I closed the map knowing autosave hit about 6 times and I saved it about 10 times.
16. I opened the map to see 16 saves ago!
17. I got pissed and tried again, still didn't show up.
18. Watching Black Boxes now...