Last time I used Windows, it's filenames were not case sensitive. So, lowercase or uppercase shouldn't matter. I can only guess whats going wrong. Maybe you have several op2 installs. And when using shortcuts its possible to forget where they point to. Another guess would be that some recent version of Windows changed the dll search pattern, i.e. it may not look for the dll in the Outpost2 installation directory. If that is the case, settings some compatibility mode may help.