AddBook If your application uses MFC in a shared DLL, and your application is in a language other than the operating system s current language, you will need to copy the corresponding localized resources MFC42XXX.DLL from the Microsoft Visual C++ CD-ROM onto the system or system32 directory, and rename it to be MFCLOC.DLL. (\"XXX\" stands for the language abbreviation. For example, MFC42DEU.DLL contains resources translated to German.) If you don t do this, some of the UI elements of your application will remain in the language of the operating system.