problems with assembly

[Furnu87]

Hey, I need a little help.
the problem is this: in a set there are a subaxieme and a particular that has two configurations. the form of this particular is made taking as reference the subaxieme. then inside the axieme I change part, within the part tree and try to change it. I have to take a path in 3d for the sweep but when I go on the parts of the subaxieme to take relationships, on the top right I get a message (not in the usual way of error) with written: "Impossible to use the selection. if you allow this selection you would create a contextual conflict, as mentioned above."
I had already done this kind of relationship with this part when I hadn't created the second configuration yet.

 

[re_solidworks]

I think that part has external references pointing to another group or to another part (in the case of component inserts).
using multiple references can work without doing anything, but I would investigate where there are other references and especially where they point. eye that with multiple references combine large scratches. . .