d3: No se puede leer la propiedad 'peso' de indefinido en la implementación de d3.force

Entiendo que la pregunta se ha hecho un millón de veces. Sin embargo, no puedo entender cuál es el problema. Estoy tratando de replicar el gráfico de fuerza dirigida como se indica en el siguiente enlace [http://bl.ocks.org/paulovn/9686202font>[1] El enlace jsfiddle eshttp://jsfiddle.net/k8a3dyuL/ No puedo entender por qué recibo este error.

Creé un objeto json de muestra para el que funcionó como se esperaba. Puedo establecer una conexión entre los nodos.

"nodes": [
{
  "index": 0, 
  "links": [
    1,
    2,
    3
    ], 
  "score": 7.35923957824707, 
  "level": 3, 
  "title": "Blood Diamond", 
  "cover": "http://d3gtl9l2a4fn1j.cloudfront.net/t/p/w342/wRamTzV6udKaMXrspxqOuo02zk0.jpg", 
  "label": "Blood Diamond (2006)", 
  "director": "Edward Zwick", 
  "cast": "Leonardo DiCaprio, Djimon Hounsou, Jennifer Connelly, Arnold Vosloo, David Harewood, Jimi Mistry, Michael Sheen, Marius Weyers, Stephen Collins, Ato Essandoh", 
  "year": 2006, 
  "duration": "143 minutes", 
  "genre": "Action, Drama, Adventure, Thriller", 
  "id": 1768448
},
{
  "index": 1, 
  "links": [

  ], 
  "score": 7.812180042266846, 
  "level": 2, 
  "title": "Casablanca", 
  "cover": "http://d3gtl9l2a4fn1j.cloudfront.net/t/p/w342/sm1QVZu5RKe1vXVHZooo4SZyHMx.jpg", 
  "label": "Casablanca (1942)", 
  "director": "Michael Curtiz", 
  "cast": "Humphrey Bogart, Ingrid Bergman, Paul Henreid, Claude Rains, Conrad Veidt, Sydney Greenstreet, Peter Lorre, Madeleine Lebeau, Dooley Wilson, Joy Page", 
  "year": 1942, 
  "duration": "102 minutes", 
  "genre": "Drama, Romance, War, Crime", 
  "id": 1750024
},
{
  "index": 2, 
  "links": [
    0
  ], 
  "score": 7.167639255523682, 
  "level": 2, 
  "title": "Lonely Hearts", 
  "cover": "http://d3gtl9l2a4fn1j.cloudfront.net/t/p/w342/wxsyl5wjobtYhll3rf5nGuC4kBN.jpg", 
  "label": "Lonely Hearts (2006)", 
  "director": "Todd Robinson", 
  "cast": "John Travolta, James Gandolfini, Salma Hayek, Jared Leto, Laura Dern, Dan Byrd, Alice Krige, Dagmara Dominczyk, Bailee Madison", 
  "year": 2006, 
  "duration": "108 minutes", 
  "genre": "Drama, Romance, Thriller, Crime", 
  "id": 1758379
}, 
{
  "index": 3, 
  "links": [
    1
    ], 
  "score": 7.595, 
  "level": 3, 
  "title": "Some Movie", 
  "cover": "http://d3gtl9l2a4fn1j.cloudfront.net/t/p/w342/wRamTzV6udKaMXrspxqOuo02zk0.jpg", 
  "label": "Some Movie", 
  "director": "Edward Zwick", 
  "cast": "Leonardo DiCaprio, Djimon Hounsou, Jennifer Connelly, Arnold Vosloo, David Harewood, Jimi Mistry, Michael Sheen, Marius Weyers, Stephen Collins, Ato Essandoh", 
  "year": 2006, 
  "duration": "143 minutes", 
  "genre": "Action, Drama, Adventure, Thriller", 
  "id": 1768448
}
],
"links": [
{
  "source": 0, 
  "target": 2, 
  "weight": 0.9770450592041016
},
{
  "source": 0, 
  "target": 3, 
  "weight": 0.9770450592041016
},
{
  "source": 1, 
  "target": 1, 
  "weight": 0.9770450592041016
}
]
}

No funciona

{
"nodes": [{
    "index": 897,
    "links": [22,
    806,
    897],
    "score": "NA",
    "level": 1,
    "title": "Customer position",
    "cover": "comapny name",
    "label": "label",
    "director": "dir",
    "cast": "cast",
    "year": 2000,
    "duration": 2,
    "genre": "NA",
    "id": 897,
    "weight": 1
},
{
    "index": 737,
    "links": [737,
    869],
    "score": "NA",
    "level": 1,
    "title": "Customer position",
    "cover": "comapny name",
    "label": "label",
    "director": "dir",
    "cast": "cast",
    "year": 2000,
    "duration": 2,
    "genre": "NA",
    "id": 737,
    "weight": 1
},
{
    "index": 869,
    "links": [737,
    869],
    "score": "NA",
    "level": 1,
    "title": "Customer position",
    "cover": "comapny name",
    "label": "label",
    "director": "dir",
    "cast": "cast",
    "year": 2000,
    "duration": 2,
    "genre": "NA",
    "id": 869,
    "weight": 1
}],
"links": [
{
    "source": 737,
    "target": 869,
    "weight": 0.9770450592041016
},
{
    "source": 897,
    "target": 806,
    "weight": 0.9770450592041016
},
{
    "source": 897,
    "target": 22,
    "weight": 0.9770450592041016
}
]

}

¿Cómo puedo resolver esto?