Problem with MemoryStream in .net framework 4.5

Hi friend,
when i am using .net framework 4.0 this code working fine. but in .net framework 4.5 this code is not working. what is problem?


string final_query=@"<s:Envelope xmlns:s="http://schemas.xmlsoap.org/soap/envelope/"><s:Header><Session><SessionId xmlns="http://webservices.amadeus.com/definitions">3434343</SessionId><SequenceNumber>3</SequenceNumber><SecurityToken>SSDFDFSDF2323232</SecurityToken></Session></s:Header><s:Body xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema"><Fare_MasterPricerTravelBoardSearch>
<numberOfUnit> <unitNumberDetail> <numberOfUnits>1</numberOfUnits> <typeOfUnit>PX</typeOfUnit> </unitNumberDetail> <unitNumberDetail> <numberOfUnits>250</numberOfUnit ...