Do you have the sources/project for this "internally developped DLL"? If yes, try the following: load the project for the DLL, build it and hit F5, VS should ask you to specify the executable you want to test your DLL with (if it doesn't, you can specify that somewhere in the project settings, can't recall where now), browse for your exe, select it and let it run (make it so it will load the DLL you just built, like, placing the executable right next to the DLL) and see if there are any exceptions thrown, check the debugger's output window too for any hints, maybe you will see something useful. > The problem with computers is that they do what you tell them to do and not what you want them to do. < > If it doesn't matter, it's antimatter.<