paths is a pointer, as per your definition.

path_info *paths

When you do

global_routing_info[i].paths = (path_info *) malloc ( sizeof ( path_info ) );

You now have an array of paths.

In order to access an element of path using the array notation [], you need to use the . not the ->

So its
global_routing_info[neighbor].paths[no_paths].path_id = path;

not

global_routing_info[neighbor].paths[no_paths]->path_id = path;