ASP.NET 2.0 Compilation Error BC30002: Type is not defined

First of all, let me explain the situation, I know this is a bit complicated. And I apologize for my poor English.

I have created a dll library which contains the classes I created. I tested the library with Console Ap开发者_如何学Cplication and web site created with Visual Studio 2005, everything works fine.

So I copied the dll to the "Bin" folder of a running ASP.NET 2.0 web site, added reference to the dll file, imported the namespace, then trying to initiate instances of objects in the dll.

The following occurred, Compilation Error BC30002: Type is not defined.

Same error shows up when I tried to create instances of another object of a new class, which is place in the "App_Code" folder of the same web site.

On the same web site, I have a third party dll library, I did exactly the same thing for that third party library and it works fine.

I am not sure why my own dll library (in the "Bin" folder) and classes (in the "App_Code" folder) do not work.

Please give me some hints how I can solve the problem.

Just a wild guess but maybe a name-space conflict between classes in your library and those in App_Code?