Then probably missing a reference to Microsoft.Csharp.dll .....

>Yes, I'm using .NET 4.0 - I'm using dynamics in other contexts and all is well.
>
>>>Here's another problem - I have code of the form:
>>>

>>>dynamic newValue = a.SomeFunction(parm1, parm2) * 3;
>>>

>>>where SomeFunction() is returning a dynamic value (because it can return values of differing types). The documentation seems to say that this should work, but I am getting a compiler error saying that "One or more types required to compile a dynamic expression cannot be found. Are you missing a reference?" I'm not sure how to clear this message.
>>>
>>>Any clues?
>>
>>Maybe targeting a framework version that does not support dynamic ? (check that you are targeting .Net 4)