I suspect I'm doing something stupid, so I hope this is the right place to post the problem. How do I get rid of the shadows from the fire when using the fireplace from Sandworld? They look like the shadows of fan blades come out from the fireplace.

D'oh! Almost as soon as I posted that, I remembered that I could unclick "casts shadows" under Properties. It looks better now, but it means the rocks don't cast shadows either.

The picture you have posted appears to be a preview. Try rendering it in firefly with auto setting set to final and see what you get. Shadows often look weird in preview but turn out fine when rendered.

Thanks for suggesting that. It does look fine in firefly. I was planning to use it in comic book mode, so if I do, I'll either ignore the absence of shadows around the stones or touch up the render in Photoshop.