Grasshopper Breakpoint: Travelling Salesman

Hi,

I'm new to Grasshopper and was trying out an Ex-Lab video tutorial on the Travelling Salesman. Should be quite straight forward but my clusters are coming up with a Grasshopper Breakpoint error reading:

One of the supplied items could not be converted:

Parameter type: GH_Point

Supplied type: GH_Integer

Because of this error, I am unable to form connection lines between points.

Can anyone tell me why please?

I have attached an image of the definition and error pop-up.

Thank you in advance.