TurboActivate.dll is not an "assembly". It's a native library. That means you can't add it like that. For using TurboActivate see the articles and the examples: https://wyday.com/limelm/help/using-turboactivate/
Long story short: you need to add the TurboActivate class to your app, which in turn calls the native TurboActivate.dll. This is covered in every single one of our articles (see the article for the programming language you're using).