String Construtor String(Char[] value) doesn't work?

So for some reason that I can't determine I'm unable to use the New String(char[] value) function.  I tried this expression in my immediate window while debugging a Windows Mobile 6 .Net 3.5 application, and this is what I got:

?new string(new char[]{'1'})

A first chance exception of type 'System.InvalidOperationException' occurred in mscorlib.dll

'new string(new char[]{'1'})' threw an exception of type 'System.InvalidOperationException'

    base {System.SystemException}: {"InvalidOperationException"}

If I typed the same expression into a normal C# desktop app .Net 3.5 application, this is what I got:

?new string(new char[]{'1'})

'new string(new char[]{'1'})' threw an exception of type 'System.ArgumentException'

    base {System.SystemException}: {"Only NewString function evaluation can create a new string."}

    Message: "Only NewString function evaluation can create a new string."

    ParamName: null

I'm exteremly puzzeled.  Anyone have any ideas?