Estou recebendo esse erro no boostrap-treeview.js: 267 ao recuperar dados JSON para o meu boostrap-treeview.

$(document).ready(function() {
    $.ajax({ 
        url: "js/category_data.php",
        method:"POST",
        dataType: "json",            
        success: function(data) {
            $('#doctypesTree').treeview({ data: data });
        }    
    });
});

Os dados JSON são os seguintes:

{
    "2":{
            "id":"12",
            "text":"Certified copy",
            "Description":"","root":"0"
        },
    "3":{
            "id":"13",
            "text":"Charter",
            "Description":"",
            "root":"0"
        },
    "4":{
            "id":"14",
            "text":"Codicil (will)",
            "Description":"",
            "root":"0"
        },
    "5":{
            "id":"15",
            "text":"Cohabitation agreement",
            "Description":"",
            "root":"0"
        },
    "6":{
            "id":"16",
            "text":"Collateral assurance",
            "Description":"",
            "root":"0"
        },
    "7":{
            "id":"17",
            "text":"Commercial invoice",
            "Description":"",
            "root":"0"
        },
    "8":{
            "id":"18",
            "text":"Complaint",
            "Description":"",
            "root":"0"
        },
    "9":{
            "id":"19",
            "text":"Conservation easement",
            "Description":"",
            "root":"0"
        },
    "10":{
            "id":"20",
            "text":"Consignee",
            "Description":"",
            "root":"0"
        },
    "11":{
            "id":"21",
            "text":"Consumer complaint",
            "Description":"",
            "root":"0"
        },
    "12":{
            "id":"22",
            "text":"Contract",
            "Description":"",
            "root":"0"
        },
    "13":{
            "id":"23",
            "text":"Contractual term",
            "Description":"",
            "root":"0"
        },
    "14":{
            "id":"24",
            "text":"Contractual terms in English law",
            "Description":"",
            "root":"0"
        },
    "15":{
            "id":"25",
            "text":"Florence Annie Conybeare",
            "Description":"",
            "root":"0"
        },
    "16":{
            "id":"26",
            "text":"Copyright transfer agreement",
            "Description":"",
            "root":"0"
        },
    "17":{
            "id":"27",
            "text":"Countersign (legal)",
            "Description":"",
            "root":"0"
        },
    "18":{
            "id":"28",
            "text":"County Court judgment",
            "Description":"",
            "root":"0"
        },
    "19":{
            "id":"29",
            "text":"Credit Support Annex",
            "Description":"",
            "root":"0"
        },
    "20":{
            "id":"30",
            "text":"Customs declaration",
            "Description":"",
            "root":"0"
        },
    "21":{
            "id":"31",
            "text":"Bills",
            "Description":"",
            "root":"0",
            "nodes":[
                        {
                            "id":"4",
                            "text":"Bill of costs",
                            "Description":"This type gather all documents related to costs","root":"31"
                        },
                        {
                            "id":"5",
                            "text":"Bill of sale",
                            "Description":"","root":"31"
                        }
                    ]
        } 
}

estou usandoVisualização em árvore do Bootstrap

Alguma ideia