This is the Error Code I Cannot Fix: {SM5} (NodeTextureSampleParameter2) Param2D> Requires Texture2D

I recently purchased this asset pack off the marketplace:

I was able to open the demo project perfectly fine, but when I tried to import assets into my own project, I couldn’t. Elsewhere I read that it isn’t possible to import .uasset and .umap extensions. So I moved over the files into the project directly on the hard drive, which worked.

Yay! I finally moved over my purchased assets into my own project! But my current problem is this: I cannot drag and drop anything from my content browser into my level editor. Each time I drag something, it turns to the grey checkered ball and I can’t do anything with it.

When I click edit on anything I added to the content browser from the Research Center I bought, it always shows the error, “{SM5} (NodeTextureSampleParameter2D) Param2D> Requires Texture2D” I don’t know how to fix it.

I have found very little on how to solve this problem. Also, I am relatively new to game development, so I am not 100% clear on all the lingo and terminology, so please try to explain things as simple as possible.

Please help me, this is driving me insane!

It looks like you just copied assets into new project, but missed folders structure or location. As result - meshes can’t find materials, and materials can’t find textures.
You should open project you purchased, select required assets, press right mouse button and select “migrate” option. Then specify “content” folder of new project.