Expression must have a class type(working with linked lists)

Have problems with this snippet of code. I keep getting error "expression must have a class type" on the third line.

if (users.find("I")!=string::npos)
        {
            int spot = atoi((users[3]).c_str());
            string pot = string(users.substr(2));
            stringstream spot(pot);
            string data;
            cin>>data;
            list.insertAfter(list.getNode(spot),data);
        }