Alright, I looked into some problems and I think I have some temporary solutions:
1. LOADING: I have implemented two things in the client (MAKE SURE IT'S Client Version: 2.022) which allow you to force loads of cards a) clicking on a "LOADING" card should force it to ask for the data again and b) typing /loadfix will force it to reload ALL blank cards. This ought to help.
2. Trading locations is fixed, I think.
As for people having trouble playing, I'm not sure how to go about fixing that. It tends to happen to a specific person over and over, but not to anyone else, so it's hard to figure out. Java seems to be very confusing to work with across platforms and such - for instance, one of my friends, whenever he plays CMC all the text is grey and larger for some reason.
EDIT: Quick fix (2.023) for the three cost-lowering locations. I forgot about the mana check in the client...
EDIT THE SECOND: Quick fix (2.024) MAY fix the 'unable to target player' bug. I'm guessing that's what caused it, at least. It's something that looks like it could act in unexpected ways, but I fixed it. Regardless if it's what was causing the unable to target player bug, it was probably causing SOME bug, so whatever.
EDIT THIRD: (2.025) Fixes the Lumi revive targeting bug. I think.