>>Make sure that any dlls that the external dll depends on are also available where it is being used. i.e if you are referencing A.dll and it depends on B.dll check that there's also a reference to B.dll in the main project...
>
>It seems that the client project does reference A, but all its (public) classes. If the classes are declared public that should do no?

I see you've solved your problem - but yes, if the relevanrt methods and properties are scoped as public they are available. When mixing between C# and VB.NET there are a few exceptions - C# for example has unsigned types which are not CLS compliant.

If you know, or expect, that an assembly will be used in this way it's a good idea to mark it with the CLSCompliant attribute - that way the compiler will catch any problems.

See:http://msdn.microsoft.com/en-us/library/bhc3fa7f.aspx

>Perplexed here because I was hoping to use some lower level classes that were developed in vb referenced from a new project I intended to write in C#, be it only to overcome my aversion for curly braces. :)

:-}

(Example of unmatched curly braces!)