Hi TimW, 

I will do a bit of guessing as I don't have such problem as you. If you are following this tutorial - https://www.databricks.com/notebooks/gcp-qs-notebook.html, the issue might be, very, very old version of runtime. Try to create and use a cluster with modern version, which will be 13+. 

If you already have a modern version of cluster, and still face this issue, try to change path to the file to start with dbfs:. Like  - path "dbfs:/databricks-datasets/Rdatasets/data-001/csv/ggplot2/diamonds.csv".

Good luck