Since I have upgraded to the .NET Framework 3.5, I have seen that it is really smart. In fact, if you compile a DLL that is tight into the application, which is then used in the BIN directory, if you also compile the main DLL of the application but only send that one to the server, even if nothing new in it requires the new compilation of the DLL, that the .NET Framework will complain about the culture once the site is accessed. By that, I mean that as soon as you compile your application, there seems to be something in it that knows that a new compilation of the other DLL has been done. So, even if it is not necessary to send that DLL as well on the server, once the application is accessed, a culture error message would occur.