Asked to convert non-convertible types Error - with FamilyInstance.ByPointAndLevel

Dear Community

I have an Error occuring at the “FamilyInstance.ByPointAndLevel”-Node. And don’t know where to begin solving the Problem.
I attached a picture in between the marked red frame you can find the node additionally marked with a red arrow.
The nodes after the “FamilyInstance.ByPointAndLevel”-Node, where i want to set the familys parameters are also giving back this error: “Warning: Internal error, please report: Dereferencing a non-pointer”
Is this because of the first error?

Thank you for your Help

Looks like your inputs is not matching with input type. Drop enlarge images showing previews for each node.

@Kulkul thank you, here it is:

Ok i tested to not include insulation in my clash element lits now the error is gone. So it was because of insulation has no Level to give back?!

To set the void placeholder familys width i use “by Get Wall Width” is there any similar node for getting the ceiling and roof thicknesses?