I use the supplied dc-talk disc with a dreamcast & broadband adapter, and followed the guide, having my system setup via the XDP disc for bba support.
I don't think its hardware flaws or software, as I've tried two systems, two different bba's, and a few copys / redownloads of the game .cdi file.
Basically, whenever I'm the host of a game (i'm alone in a game), and someone joins it, I lockup and crash.
After sitting with both of my systems back-to-back, both online, with both characters capable of seeing each other in the lobby, I was successful of joining my own game 1/6 of the time.
The other 5/6 of the time;
~The character that is the "host" is frozen in place and after a minute or so, is sent back to the title screen of the game.
~The character that joins is frozen in loading, looking at the Hunters Guild room tower thing, and is eventually sent back to the lobby.
Obvious attempts at rushing this lockout (turning off the system for example) typically result in complete meseta lost from backpack, and all items not equipped lost from backpack.
Now I always assumed that this was due to me having just average internet speed. My internet is actually pretty fast, and with this game, and private, not overly-populated servers, it shouldn't really be that...
I recall that the XDP disc had alot of settings when regards to connections, but the guide here suggested just leaving everything on auto, is that still the way to go?
Is there anything I can do to halt this problem? I'd love to be able to host a stable game instead of relying of others to make for me.

Thanks in advance for any help!