I spent hours on creating a background with matte textures.
No problem, they show up in the Material and the Texture view:

Everything works.
Solid view:

Now I tried to render it and got this:

Pink textures all over the place. I have seriously no idea why Blender keeps doing this. I double checked all textures in the node trees, they are exactly where Blender points them at.
Here is the material:

but they just do not show up in the render.
I have no post-processing so far.
Here my lightpath settings:

I hope somebody can help.
Thanks in advance!

