Could be that textures in this mod are broken, I recommend taking a look at my own reupload here:
https://steamhost.cn/steamcommunity_com/sharedfiles/filedetails/?id=877098705

I've been looking for a mod like this for a LONG time. You, sir, are a godsend!

Yes, this is because I used a random sand texture from the web and apparently that got removed.
For now you can simply google for "seamless sand texture" and pick one you like, then right click the large base and the two ramps, choose "custom", replace the broken diffuse texture link and hit "import".

Due to the aforementioned bug I cannot replace this myself, have to see if I can get Sly to fix this together with me.

The beach textures seem to be missing?

Thanks!

very nice