Installing LAN adapter

I inserted a PCI Realtek RTL8139 network adapter on a PC running SCO Openserver 5.0.6.
I successfully loaded drivers and I'm trying to install the card with netconfig command, unfortunately without success.
Here are the steps I follow to install the card:
I run netconfig, from menu 'hardware' I choose the "Add new LAN adapter". In the list of tabs, I get the Realtek 8139 (software, in fact, as I said, I managed to upload it regularly). After selecting the adapter from the list, I select the speed that set to "Auto". After the confirmation of all, I get the following error: "Please verify adapter is set to the configuration just entered. No protocol stacks available on the system are supported on this device".
Have you any suggestions? I missed some step during the procedure?
Thank you all.
Vincenzo.

You do not have tcp installed. There are two versions of Openserver, host and enterprise.
Host does not have any tcp networking components and relies solely on serial ports for user connectivity. While both versions are on the cd, you need an enterprise serial number and activation key for the enterprise version to be installed.

Thank you!!