Webservice Error

[GovardhanReddy9]

I've created webservice using by code:
[WebMethod(Description = "Echo Soap Request")]
public XmlDocument EchoSoapRequest(string input)
{
// Initialize soap request XML
XmlDocument xmlSoapRequest = new XmlDocument();

// Get raw request body
Stream receiveStream = HttpContext.Current.Request.InputStream;

// Move to begining of input stream and read
receiveStream.Position = 0;
System.Text.Encoding encoding = System.Text.Encoding.Unicode;
//BinaryWriter bw = new BinaryWriter(receiveStream, encoding);
using (StreamReader readStream = new StreamReader(receiveStream,Encoding.UTF8))
{
// Load into XML documen
xmlSoapRequest.Load(readStream);

//xmlSoapRequest.Load(ConfigurationManager.AppSettin gs["CatalogXMlRootPath"] + readStream + ".xml");
}

// Return
return xmlSoapRequest;
}
}

But I got following error,if you have any error give me suggestion:

System.Xml.XmlException: Data at the root level is invalid. Line 1, position 1.
at System.Xml.XmlTextReaderImpl.Throw(Exception e)
at System.Xml.XmlTextReaderImpl.Throw(String res, String arg)
at System.Xml.XmlTextReaderImpl.ParseRootLevelWhitesp ace()
at System.Xml.XmlTextReaderImpl.ParseDocumentContent( )
at System.Xml.XmlTextReaderImpl.Read()
at System.Xml.XmlLoader.Load(XmlDocument doc, XmlReader reader, Boolean preserveWhitespace)
at System.Xml.XmlDocument.Load(XmlReader reader)
at System.Xml.XmlDocument.Load(TextReader txtReader)
at GettingLists.lsts.EchoSoapRequest(String input) in E:\Practice\Sharepoint\GettingLists\GettingLists\l sts.asmx.cs:line