>I mean in VS 'Solution Explorer' by right clicking on the file in 'References'
>In C# they are always displayed but I believe in VB you need to select 'Show all files' for the project....

You are right. In that application, Flexcel is required as I make a direct reference to it. That one was compiled for 2.0. So, it requires a declaration in a config file to force the application to compile as is. For the Web site, Flexcel is in the directory but not referenced in the Web site dll as I am using the framework whereas any reference to Flexcel occurs. That is why it does not complain when the application starts.