Odd, the UOA thing should be fixed now.
Many of my guildmates are having trouble and I'm hesitant to recommend the registry hack workaround listed in UHall.
For the ones who did eventually fix it, it seems that reinstalling UO works best.
Reinstall UO, then run the UOPatch.exe run first. Do not start off with UOA. After UO is done patching, close the client. Now try UOA and let it patch (if you haven't already) and things should be better.
Given your connection, however, I'm afraid this whole process will take you significantly longer than the rest of us. =[