It looks like you may have some damaged Operating System dependencies. Please use the Demonbuddy installer, not zip file, to re-install Demonbuddy. You can find the installer here, and you need to run it with Windows 'administrator' privileges:
I've tried to re-install it as a administrator with the installer, but the problem is still there, and after I ran the Demonbuddy, "yjbtupzftj" and "yjbtupzftj.exe.config" was added to the file.
Something about your Windows installation is not standard. Examples are a university or government computer, or a non-genuine version of the OS. It could many things. Maybe you've installed a program that has replaced the default MD5 crypto algorithm with something else. Here are a couple of articles to help you chase it: