I don't know about you, but as far as I can tell, that pretty much speaks in favor of my idea, not AdamJohnso's. You're copying the client from Untìl Uru (which is based on Prologue-generation code, and does explicitly not support either expansion pack) into a tPotS environment.
The page doesn't go into detail on why to copy this client, but as far as I can tell, "because it contains networking code missing in tPotS" is one likely conclusion.
Ah. Generally speaking when people say "the client" they refer to that *big* program, you know, the one with the graphics and the avatar and stuff like that in it. UruSetup.exe starts up the client for you. Okay... so the CC UruSetup.exe doesn't have an option to tell the client to go talk to a server, true.
If this is what you meant, I'm sorry. Trust me, AdamJohnso is referring to the other thing, called UruExplorer.exe, and so was I. I somehow did not think you were going to call the setup program "the client" given that all your other commentary about "the client" isn't about UruSetup either. Whatever. I can be the wrong one if you like.