Why did I get the error "ActiveX component can't create object: 'com.paypal.sdk.COMNetInterop.COMAdapter'" with the Classic ASP SDK?

If you’ve installed the classic ASP SDK and got an “ActiveX component can’t create object” error, this is because you don't have RegAsm and gacutil in your system PATH. Depending on your configuration, you may also see a generic error such as "paypal_base error '80131500'."

RegAsm is a program shipped with the .NET SDK that allows you to export .NET assemblies as COM objects. Gacutil is a program that ships with the .NET framework that enables you to put assemblies in the GAC (Global Assembly Cache).

When the classic ASP SDK installer runs, it tries to invoke a RegAsm command and a gacutil command. If these aren't in your PATH, the SDK DLL (paypal_base.dll) won't be registered properly on your system, and you'll see errors when ASP tries to create an instance of an SDK object.