向Couchbase数据库里面添加数据时出问题，求解答呀！！！
//配置服务器                                
                                CouchbaseClientConfiguration mbcc = new CouchbaseClientConfiguration();
                                //使用默认的数据库  
                                mbcc.Urls.Add(new Uri("http://10.10.10.37:8091/pools/default"));

                                //建立一个Client，装入Client的配置                              
                                
                                CouchbaseClient client = new CouchbaseClient(mbcc);
                                string str = "{\"POIInfo\":\"" + pair.Value.Pguid.ToString() + "_" + (m++).ToString() + "_" + (n++).ToString() + "_" + ixx.ToString() + "\",\"original\":\"" + poi.OriginalWord + "\","
                                                + "\"pguid\":\"" + poi.Pguid + "\",\"originalpinyin\":\"" + poi.OriginalPinyin + "\",\"originalfirstchar\":\"" + poi.OriginalFirstChar + "\",\"type\":\"" + poi.Type + "\","
                                                + "\"longitude\":\"" + poi.Longitude + "\",\"latitude\":\"" + poi.Latitude + "\",\"areacode\":\"" + poi.AreaCode + "\",\"poitype\":\"" + poi.POIType + "\",\"typeboost\":\""
                                                + "" + poi.TypeBoost.ToString() + "\",\"frequencyboost\":\"" + poi.FrequencyBoost.ToString() + "\",\"name\":\"" + derive.DeriveName + "\",\"derive