Why do I get a blank material in Unreal Engine 4?

When I'm adding a material to a box in UE4, the material loses its textures.

I want to add this material

To this

After I'm trying to drag & drop the material into the scene above (like in UDK) the material loses its textures and does not apply:

When opening the material in Material-builder, the same thing happens: the material loses its textures and I've got these two errors on "Stats":

[SM5] (Node TextureSampleParameter2D) Param2d> Requires Texutre2D

[SM5] (Node TextureSample) TextureSample> Missing input texture

I've searched and found a thread where they say I need to save the material again to get things right. When I click the save button, I have this error:

The current material has compilation errors, so it will not render correctly in feature level SM5.

NOTE: Using DepthFade node + Lerp and changing the blend to translucent didn't resolved my issue.

Any idea?