How to resolve an error with WCF data contract -Message = "There was an error while trying to serialize parameter - wcf

Question

I have two data contracts of same contents in two different namespaces. i have copied one datacontract to another and
passed to a particular method. but it is giving the below error and throwing exception. it is not going into that method.
Please let me know any ideas /suggestions on how to resolve this.Appreciate your help:
Exception errror:
{"Type 'System.Collections.Generic.List`1[[GlobalWcfServiceLib.TopicDetailsInfo, GlobalWcfContracts, Version=1.2.2.0, Culture=neutral,
PublicKeyToken=17c64733a9775004]]' with data contract name 'ArrayOfTopicDetailsInfo:http://CName.GlobalService/11.1/2010/11'
is not expected. Consider using a DataContractResolver or add any types not known statically to the list of
known types - for example, by using the KnownTypeAttribute attribute or by
adding them to the list of known types passed to DataContractSerializer."}
Message = "There was an error while trying to serialize parameter
http://CName.SharedServices.DBServiceLib:subscriptionDataContract.
The InnerException message was 'Type 'System.Collections.Generic.List`1
[[GlobalWcfServiceLib.TopicDetailsInfo,
GlobalWcfContra...
//////
Here is my scenario : i am copying the data from dc to new data contract as below. after copying , when i am executing the createsubscriptions method i am getting the above mentioned error. i have given the details of data contract and error attached to this question. please refer to that as well.
Method1(SubscriptionDataContracts dc)
{
SubscriptionDataContract subscriptionDataContract = new SubscriptionDataContract();
List<SubscriptionTopicInfo> topicsInfo = dc.TopicList;
List<SubscriptionTopic> newTopicsList = new List<SubscriptionTopic>();
subscriptionDataContract.ExtensionData = dc.ExtensionData;
subscriptionDataContract.UserID = dc.UserID;
for (int i = 0; i < topicsInfo.Count; i++)
{
SubscriptionTopic topic = new SubscriptionTopic();
topic.DBHandle = topicsInfo[i].DBHandle;
topic.Topic = topicsInfo[i].Topic;
topic.Target = topicsInfo[i].Target;
newTopicsList.Add(topic);
}
subscriptionDataContract.TopicList = newTopicsList;
CreateSubscriptions(subscriptionDataContract); //getting the above mentioned error in another dll after going into this method
}
////////////////////////////////
//My data contract
[DataContract(Name = "TopicDetailsInfo", Namespace = "http://CName.GlobalService")]
[Serializable]
public class TopicDetailsInfo
{
protected object topic;
protected object baseObjectType;
[DataMember]
public object BaseObjectType
{
get
{
return baseObjectType;
}
set
{
baseObjectType = value;
}
}
[DataMember]
public object TopicID
{
get
{
return topic;
}
set
{
topic = value;
}
}
static public TopicDetailsInfo CreateTopic<T, mT>(IComparable<T> objectType, IComparable<mT> objectID)
{
var topicDetails = new TopicDetailsInfo();
topicDetails.BaseObjectType = objectType;
topicDetails.TopicID = objectID;
return topicDetails;
}
}
[DataContract(Name = "SubscriptionTopicInfo", Namespace = "http://CName.GlobalService")]
[KnownType(typeof(List<TopicDetailsInfo>))]
[Serializable]
public class SubscriptionTopicInfo
{
private object topic;
private object target;
private object creator;
[DataMember]
public object Topic
{
get
{
return topic;
}
set
{
topic = value;
}
}
[DataMember]
public object Target
{
get
{
return target;
}
set
{
target = value;
}
}
[DataMember]
public object DBHandle
{
get
{
return creator;
}
set
{
creator = value;
}
}
static public SubscriptionTopicInfo CreateSubscriptions<T, mT, nT>(IList<TopicDetailsInfo> topic, IComparable<mT> target, IComparable<nT> handle)
{
var subscriptionTopic = new SubscriptionTopicInfo();
subscriptionTopic.Target = target;
subscriptionTopic.Topic = topic;
subscriptionTopic.DBHandle = handle;
return subscriptionTopic;
}
}
[DataContract(Name = "SubscriptionData", Namespace = "http://CName.GlobalService")]
[KnownType(typeof(List<SubscriptionTopicInfo>))]
[Serializable]
public class SubscriptionDataContracts : IExtensibleDataObject
{
private ExtensionDataObject extensionDataObjectValue;
[DataMember]
public string UserID
{
get;
set;
}
[DataMember]
public string ProjectID
{
get;
set;
}
[DataMember]
public string FromDiscipline
{
get;
set;
}
[DataMember]
public string ModuleID
{
get;
set;
}
[DataMember]
public string SessionID
{
get;
set;
}
[DataMember]
public List<SubscriptionTopicInfo> TopicList
{
get;
set;
}
public ExtensionDataObject ExtensionData
{
get
{
return extensionDataObjectValue;
}
set
{
extensionDataObjectValue = value;
}
}
}