Error message when opening a recordset with a strem containing xml

I have a problem when trying to open a recordset with a stream including
xml 
content. 

The code line that triggers the error looks like this:

tempRecordsetClass.Open(xmlStream, tempRecordsetClass.Source, 
tempRecordsetClass.CursorType, tempRecordsetClass.LockType, (int) 
ADODB.CommandTypeEnum.adCmdUnspecified);

I get the following error message:

System.Runtime.InteropServices.COMException
Message = [Microsoft][ODBC Driver Manager] Data source name not found and
no 
default driver specified

I have also modified some of the parameters so it looks like this: 

tempRecordsetClass.Open ((ADODB._Stream)xmlStream, noParam, 
ADODB.CursorTypeEnum.adOpenUnspecified,
ADODB.LockTypeEnum.adLockUnspecified, 
(int)ADODB.CommandTypeEnum.adCmdUnspecified);

where noParam is a system object with the value 
"System.Reflection.Missing.Value"

But then I get another error message instead:

System.InvalidCastException
Message = Unable to cast COM object of type 'System.__ComObject' to class 
type 'ADODB.RecordsetClass'. COM components that enter the CLR and do not 
sup****t IProvideClassInfo or that do not have any interop assembly
registered 
will be wrapped in the __ComObject type. Instances of this type cannot be 
cast to any other class; however they can be cast to interfaces as long as

the underlying COM component sup****ts QueryInterface calls for the IID of
the 
interface.

Now I need your help, please.

The total content of the module is the following:

	public virtual Recordset toRecordset(Do***ent doc, Recordset rsEmptyAI)
		{
			System.String xml = null;
			Recordset rsNewAI = new Recordset();
			_Stream xmlStream = new Stream();
			System.Object noParam = new System.Object();
			noParam = System.Reflection.Missing.Value;
			System.String schemaText = null;
			
			ADODB.RecordsetClass rsUnmodifiedWFC = new ADODB.RecordsetClass();
			ADODB.RecordsetClass rsNewWFC = null;
			
			try
			{
				// save the empty recordset to a stream
				rsEmptyAI.Save(xmlStream, PersistFormatEnum.adPersistXML);
				schemaText = xmlStream.ReadText((int)StreamReadEnum.adReadAll);
				
				// get just to <rs:data>
				schemaText = schemaText.Substring(0, 
(schemaText.IndexOf(com.volvo.vtc.sprint.bussvc.assembly.copybtwfactories.xml.IElements.rs_data))
- (0));
				
				xml = XMLHelper.toXML(doc);
				
				// get from <rs:data> to end
				xml = 
xml.Substring(xml.IndexOf(com.volvo.vtc.sprint.bussvc.assembly.copybtwfactories.xml.IElements.rs_data),

(xml.Length) - 
(xml.IndexOf(com.volvo.vtc.sprint.bussvc.assembly.copybtwfactories.xml.IElements.rs_data)));
				xml = schemaText + xml;
				
				// get a new stream
				xmlStream = new Stream();
				
				// open the stream
				xmlStream.Open(noParam, ADODB.ConnectModeEnum.adModeUnknown, 
ADODB.StreamOpenOptionsEnum.adOpenStreamUnspecified, null, null);
				
				// write to a stream
				xmlStream.WriteText(xml, ADODB.StreamWriteEnum.adWriteChar);
				xmlStream.Flush();
				
				// set cursor at the begining
				xmlStream.Position=0;
				
				ADODB.RecordsetClass tempRecordsetClass;
				tempRecordsetClass = rsUnmodifiedWFC;
				tempRecordsetClass.Open(xmlStream, tempRecordsetClass.Source, 
tempRecordsetClass.CursorType, tempRecordsetClass.LockType, (int) 
ADODB.CommandTypeEnum.adCmdUnspecified);
				
				rsNewWFC = (ADODB.RecordsetClass)rsEmptyAI;
				
				// copy the unmodified recordset to the empty, then it will be in
status 
new
				this.copyRecordData(rsUnmodifiedWFC, rsNewWFC);
				
				rsNewAI.Source =((System.Object) rsNewWFC.DataSource);
			}
			catch (System.Exception t)
			{
				throw SPServerException.toServerException(t);
			}
			
			return rsNewAI;
		}