Please download the latest version of the DLL to address this issue and let us know if you have any more problems. You should now be able to add the DLL as a reference in VS2017 community edition. You will however not be able to debug any of the LicenceKey methods as it will cause a 'fatal error' exception in VS due to the copy protection. All you need to do is comment out the calls to LicenceCheck until you are ready to build your final release version. At this point you can uncomment the LicenceCheck code and build the release version. You will then be able to launch your application by running the executable from within the bin\release folder of your project and it will run as normal with the licence check included. If this all works ok then you can replace the KMSC.dll file with the release version of the KMSC dll. Zip the release files up and upload them to the website and all should be good.
The code you should comment out until you are ready to build the release version is this (copied from quantum-key.net home page
https://quantum-key.net):
LicenceCheck licenceCheck = new LicenceCheck();
licenceCheck.ShowDialog();
if (!licenceCheck.IsClosing)
{
if (licenceCheck.IsLicenceValid)
{
// code to launch full version of your software
}
else
{
// code to launch demo version of your software
}
}