The missing symbol the compiler was looking for was CreateXmlReader, I know the compiler indicated that the problem was in your dialog class, it's a common red herring, but once you know how to read these linker error messages, it gets easier :-) If adding a library path instead (if all you have is the .lib file), you will want to check that the library is added for debug and release builds. Configuring a project dependency as in the previous solution is thus best.
Conrad - The world waits for you to stick your neck out, it's not easy. But once you actually stand up, you do get noticed. http://www.plcsimulator.org/