Warning: Internal error, please report: Dereferencing a non-pointer error help

Hello. I am a beginner Dynamo user and I am getting this error when trying to build a graph for creating floors from rooms. This error is happening in both the graph given to me and in the one I have created from a user video. Is this a Dynamo installation error or is this common? How can I fix it?

Any help would be greatly appreciated!


Here is the non-pointer error:

Try the flatten node after element.geometry. You possibly need to remove the “Empty List”.

Just tried it, now this…