error adding reference in .net 3.5

Im trying to add a reference to a dll i downloa开发者_JAVA技巧ded which I want to use for some sftp work. as soon as i add it i get "could not load file or asse3mble....failed to grant minimum permission requests" Is this to do with my own account permissions?

thanks

DD

Your question isn't very detailed but a guess:

If you download an assembly from the internet your machine will not trust it. This is all to do with CAS (Code Access Security). You can find a lot of information about this here.