Environment.is64bitoperatingsystem is not a member of system.environment

if system.environment.is64bitoperatingsystem.tostring=true Then

msgbox("this is 64bit Operating System")

End if 

above given code is working in Visual Basic Express Edition 2010 as per the video

http://www.youtube.com/watch?v=VjH1t1BNaKs

i try this code in visual studio 2010 Professional Edition

But it not working

environement.is64bitoperating is not a memeber of system of environment

thanks