In which way must this program accessed? I mean, via a client program which contacts the server via network? If so, are the clients / server on the same network (WLAN, LAN)?
If yes, you can simply install the program on windows server, no matter if active directory exists. The your client (if a client program exist, or a webpage is used, I don't know), can access the program.
You just need to open the right port on your firewall to permit comunications.