When I typed in the first sample code from C# in a Nutshell, I got a puzzling error message stating that I was trying to use the namespace ('using System;') as a variable. I say this with complete understanding that trapping errors and writing good messages to go with them is challenging, to say the least. Ignoring the supposed error is much preferable to receiving a misleading message--and may be easier to implement within LinqPad.

MSG: "CS0118 'System' is a namespace but is used like a variable"