I found the problem.
Devrims work is wonderful.
I made a mistake. I unzipped the texture package, replaced one texture tile, zipped the files again. Problem was a texture folder was created within the zip file. In other words.. .there was one extra layer and DCS couldn't acces that zipped file hence the very strange blocks, white windows in my mi8.
Instead of checking my zip file I kept creating different .dds files with gimp.
