uo51a

Ok so I thought I'd try playing a UO freeshard (I haven't played in a very long time) and this shard showed up in a google search and appeared interesting. For arguments sake (and because it is mostly true) assume I know very little about computers. I downloaded the 9th anniversary client from Origin's website and installed it. From there I started it, but prevented the patch. Then I downloaded UO51a files from this website and copied and pasted them into my uo folder replacing the files by the same name (I presume that is correct). Then I tried to run the client and recieved an error message saying UO51a was not installed correctly or something of that nature and that I needed to reinstall UO through setup.exe. Rather than playing around with this hopelessly I was curious if someone could walk me through what I did wrong and what I need to do to fix it in detail.