If you are a server host running a windows server and someone wants to use our DLL on it, you will need the following packages installed:

https://www.microsoft.com/en-us/download/details.aspx?id=30679 https://www.microsoft.com/en-us/download/details.aspx?id=52685

Make sure you are downloading the right version for your server. You will most likely need the x86 version for a 32-Bit SRCDS instance, even if you are running on a 64-Bit Windows installation.

To be safe, it is recommended ( but completely optional ) to also download Visual Studio to cover any basic packages or service pack features that may be missing across different Windows copies.