Thank you for your fast reply.
So, do I need to set up an Account at sylverant.net to play online?
You don't strictly have to do so to play on the Dreamcast version, but I do encourage you to do so. There's one nice feature that can only be enabled if you have an account (namely automatic character data backups), and there are other features I plan to work on at some point in the future that will also be tied to having an account. Also, to play any other version of the game (PC, Gamecube, (and in the future) Blue Burst), you do need an account.
Do I just use the Serial Number and Access Key that came with the Game or do I need different ones?
Yes, just use the Serial Number/Access Key pair that came with the game.
Is there an Setup Beginner Guide somewhere? I am a little lost right now D:
Well, if you're using the patcher disc, I think you should have everything you need to know now. If not, feel free to ask. I don't have any sort of beginner's guide, as most of the people around (that I know of anyway) have played on other private servers in the past and have been through the whole drill with them. The patcher disc helps out with a few things too (like making it so you don't have to use any strange dns redirection or whatnot).
BTW - using plain files and BootDream did the trick! Great. I have no idea why it did not work with the cdi image, tho...
Glad to hear that worked. It could just be the way that image is formatted not agreeing with something in your cd burner or something like that. I don't actually ever burn anything from images, as I said in my previous post, so I just put up what people tell me works.