Error : Boolean System.Runtime.Serialization.DataContractAttribute .get_IsReference()

[rajputamit]

Hi,
I have downloaded Ext.Net dll from
http://www.ext.net/download/1-0-0/Ext.NET.zip

but I am getting below error for my Gridpanel.Please help.
MESSAGE: Method not found: 'Boolean System.Runtime.Serialization.DataContractAttribute .get_IsReference()'.
PAGE: ~/HR/WebForm2.aspx
SOURCE: Newtonsoft.Json
TARGETSITE: Void InitializeContract(Newtonsoft.Json.Serialization.J sonContract)
STACK TRACE: at Newtonsoft.Json.Serialization.DefaultContractResol ver.InitializeContract(JsonContract contract)
at Newtonsoft.Json.Serialization.DefaultContractResol ver.CreatePrimitiveContract(Type objectType)
at Newtonsoft.Json.Serialization.DefaultContractResol ver.CreateContract(Type objectType)
at Newtonsoft.Json.Serialization.DefaultContractResol ver.ResolveContract(Type type)
at Newtonsoft.Json.JsonSerializer.SerializeInternal(J sonWriter jsonWriter, Object value)
at Newtonsoft.Json.JsonConvert.SerializeObject(Object value, Formatting formatting, JsonSerializerSettings settings)
at Ext.Net.BaseParameter.ValueToString()
at Ext.Net.CustomConfigJsonConverter.WriteJson(JsonWr iter writer, Object value, JsonSerializer serializer)
at Ext.Net.ClientConfig.ToExtConfig(Object obj, ConfigOption configOption)
at Ext.Net.ClientConfig.Process(Object obj)
DATA: System.Collections.ListDictionaryInternal
INNER EXCEPTION:
----------Log Services Stopped

[mostafa]

update your framework