Texture dissapears completelly

First , I must say that I do always save x5 times to make sure before closing any blend

but everytime I texture this terrain all the colours dissapear when i open the file again … this is so nerving

Did you save the blend file x5 times or the actual texture x5 times before closing the blend file.
Just saving the blend file will not save the texture.

Looking at the screenshot and the image editor window I can see that you have not currently saved that image file (see the menu where the Image entry has a * after it)


You have to save the Texture from Uv-Image editor in Menuline - image - Save as Image.

If You want to pack it with Blender You can use the External Data in Menuline - File

Just remember You always have to save texture from Uv - Image editor when You have edited it.