Vectorworks has two different installers available for the two different types of Vectorworks licenses that are available.
Most users have the E series license but some people have a B/C/G series license. If you download the installer that doesn't match your serial number, the installer will tell you that your serial number is invalid.
If you are a Vectorworks Service Select member, you will have access to both installers so this image should help clarify which to download:
