What is NO_CUR_BB -- no current bulletin board exists?

I have been receiving these error messages when I run manually some times. I’ve been to extract the geometry from a floor element I’ve placed in Revit. Does anyone understand what it means? I suspect Dynamo is not sensing the floor I’ve placed, but I’ve double checked and I am very sure there is a floor on Revit. Thank you!

The error message on the Dynamo nodes are:
Warning: Element.Geometry operation failed.
Value cannot be null.
Parameter name: source

The error on the python node is:
Warning: IronPythonEvaluator.EvaluateIronPythonScript operation failed.
Traceback (most recent call last):
File “”, line 23, in
StandardError: Unable to compute edge from curve : NO_CUR_BB – no current bulletin board exists

The relevant lines of code are:
floorCat = IN[0]
for i in floorCat:
geo = i.Solids <-- line 23

Sometimes, the python error message would be (for the same affected line):
Warning: IronPythonEvaluator.EvaluateIronPythonScript operation failed.
Traceback (most recent call last):
File “”, line 27, in
StandardError: Unable to create entity! : ACIS_EXCEPTION_ACCESS_VIOLATION – Access violation

Thanks for your help! It have returned to a previously saved file and worked on that.